Probability: Conditional Probability Formula
Question 1: Events E and F have P(E)=0.4, P(F)=0.8, P(F/E)=0.6. Find P(E/F).
Solution: Use formula P(E∩F) = P(F/E)·P(E) = P(E/F)·P(F)
- P(E∩F) = 0.6 × 0.4 = 0.24
- P(E/F) = 0.24 / 0.8 = 0.3
Isosceles Triangle: Ratio and Heron's Formula
Question 2: Equal sides:unequal side = 6:11, perimeter = 46 cm. Find approximate area.
- Sides = 12, 12, 22 cm
- Semi-perimeter s = 23 cm
- Heron: √[23(11)(11)(1)] = √(23×121) = 11√23 ≈ 11×4.796
- Area ≈ 53 cm² (slightly less than 55)
Profit & Discount: Successive Percentage Change
Question 3 & 5: Calculate net profit using formula x - y - xy/100. For more on profit formulas, see Profit & Loss: Solve Aptitude Problems Fast with Formulas & Tricks.
- Q3: First pen 70% profit + 9% discount → net profit = 70 - 9 - (630/100) = 61 - 6.3 = 54.7%
- Q5: Marked 21% profit, 12% discount → net = 21 -12 - (21×12/100) = 9 - 2.52 = 6.48%
Election & Valid Votes
Question 4: 15% didn't vote, 10% invalid among voters. Winner got 72% of valid votes = 8262.
- Valid votes = 8262 ÷ 0.72 = 11,475
Train Speed & Bridge Length
Question 6 & 7: 220m train crosses post in 11s → speed = 20 m/s
- Same train crosses bridge in 18s: (220 + L) / 20 = 18 → L = 140 m
Relative Speed & Time
Question 8: Train 50% faster than car, train stops 12.5 min. Distance 75 km, same arrival time.
- Speed ratio train:car = 3:2 → time ratio = 2:3
- Time difference = 12.5 min = 1 unit → car time = 37.5 min = 5/8 hr
- Car speed = 75 ÷ (5/8) = 120 km/hr
Trigonometry Identity
Question 13: Given (1 - cosθ)/sinθ = 1/5, find (1 + cosθ)/sinθ
- Identity: product = 1 → inverse = 5
Ratio: Income, Expenditure, Savings
Question 14: Income ratio (A:B) = 3:5, Expense ratio = 1:3, both save ₹10,000. For more on ratios and proportions, visit Understanding Averages, Ratios, and Proportions in Mathematics.
- Cross-multiply: (3×3 - 5×1) = 4 units = 20,000 → 1 unit = 5,000
- Bharat's income = 5 × 5,000 = ₹25,000
Time & Work Efficiency
Question 18: Abhi 50 days, Varun 25% more efficient (ratio 4:5). Work = 200 units.
- Together 8 days → 9×8 = 72 done; Charu does remaining 128 in 6.4 days → efficiency 20
- 75% of 200 = 150; Varun+Charu = 25; Days = 150/25 = 6 days
Exponents & Powers
Question 19: 4^(2x-16) × 4^(x-5) = 64 = 4³
- Equate powers: 3x - 21 = 3 → x = 8
Concentric Circles & Triplets
Question 28: Radii 34 cm (inner) and 50 cm (outer). BC = 32 cm chord on inner circle.
- Use 8-15-17 and 3-4-5 triplets
- Distance from center to BC = 30 cm
- Half chord on outer = 40 cm → full AD = 80 cm
Quadratic Roots
Question 25: Roots -1 and -2 satisfy 3x² + px + q = 0
- Substitute → p - q = 3 and 2p - q = 12 → p = 9, q = 6
- 3p - 2q = 27 - 12 = 15
Hello everyone, welcome to Mentor, my YouTube channel. How are you friends? How is everything? What's up? Are you
all doing well? That's how it goes, right? So, everyone, please join in. >> Hello everyone, welcome! Come on,
everyone get here quickly. Then we will start today's test paper. This is mock test eight for ALP. We have reached the
eighth test, right? And the level of the questions today is even better, isn't it? The level of questions today
is a bit higher, it will be a bit harder, so solve the questions carefully. Okay. Come on, let everyone
join. I will bring the timer quickly. We have to solve the questions without wasting time. Our main work is with the
questions. Right? Come on, everyone join quickly. And tell me, how is your preparation going? RRB JE candidates,
CAT candidates, how are you all doing? How are your exams going? Aspirant Gaurav, please give me your blessings.
Our blessings are definitely with you. Meaning, my best wishes are with you. At least tell me what you are asking
for. Come on, let everyone join. Then we will start with question number one. ALP mock test eight, the exam that is
going on from November 3rd to 5th for your Loco Pilot. It's the exam for this , right? It's the exam for this. Come
on, everyone join quickly, shall I start with the first question? Alright, here is the first question on your
screen. It's about probability, right? Events are given. Tell me the answer to this. Everyone will tell the answer to
the first question. Everyone will tell the answer to the first question. NTPC, final this time. Everyone tell the
answer to this. Everyone will tell the answer to question number one. Get NTPC done finally this time. It will
definitely be final. Right? Aspirant, it will definitely be final. Prepare comfortably this time. It will be final
. Right? Come on, everyone tell the answer. The answer to question number one. Okay, Saurabh Tiwari is saying B,
Aditya Tripathi 0.3. Very good Aditya, look, it says E and F are events such that PE, the probability of E is 0.4,
the probability of F is 0.8, and you are given P (F/E), which is 0.6. So you are asked for P (E/F), right? You are
asked for P (E/F). So, friend, do you know one thing? Do you know that the probability of P (F/E) multiplied by PE
will be equal to the intersection? The probability of P (E/F) multiplied by PF , will this be equal or not? Because
both of these will be P intersection E, intersection with F. This is what it will be on both sides, this is what it
is, this is what we have been studying, right? No problem, for those children who don't know probability, I will do a
separate marathon for it and explain it well, okay? So everyone remembers this formula, brother. So what is the value
given for P (F | E)? 0.6, P (E) you have is 0.4 and P (E | F) has to be calculated. We need to find E/F. F/E
was given. Meaning its probability was given. F/E was asked. So you multiply by E, and if EF is asked, then you
multiply by F. Into, what is the P (F) given to you? 0.8, cancel it out. Meaning it will go for two. And this
0.3, so what is the probability of P (E /F) you got? 0.3, Aditya, very good. Aditya gave the correct answer. Okay
Ashok ji, Ashok, it won't be B. You must be having trouble with the calculation. Are you calculating
something wrong? No, that will absolutely not be the case. Okay. Come on, tell me the answer to question
number second. Tell me the answer to question number second. Which method will you use and how will you do it?
Tell me quickly. The answer to question number second, and everyone should like the session once. Everyone should like
it too. Tell me the answer to question number second. Tell me the answer to question number second. It says that in
an isosceles triangle. Question number second says in an isosceles triangle if the ratio of one of the equal sides and
the unequal side is 6:11 and its perimeter is 46 cm, then the area of the triangle is approximately. The
question is telling you that in an isosceles triangle, if the ratio of one of the equal sides and the unequal side
is 6:11, then its perimeter is 46 centimeters. What will be the approximate area of the triangle?
Meaning it says that the ratio of the equal side and the unequal side is given as 6 and 11. So tell me, a
triangle will have three sides, right? And it's an isosceles, so brother, this will be 6, this will be 6, this will be
11, right? Absolutely. So what will 6 and 11 be? 17, and what will 17 and 6 be? 22, no, 17 and 6, 23, so 23, which
is the perimeter, if I sum all three, then what will this be, 12 and 11, the value of 23 is given to you as how much
? 46, meaning it goes for two. So what are these sides? This is also 12, this is 12, and this one you have is 22,
right? Is this 22 or not? Absolutely. So now, if you want, you can do it by making a right-angle triangle or you
can use the direct formula. What? Square root, we find the area using Heron's formula, right? We find the
area using Heron's. So the perimeter, semi-perimeter is 23, so 23 minus 12 is 11, 23 minus 12 is 11, 23 minus 22 is 1
, right? This is what we'll get? Absolutely. So 11 is taken out, 11 is taken out. Square root of 23, now tell
me, what is this close to? It is smaller than 25, right? It is smaller than 25 and larger than 16. So, should
I say let's assume it's around 11*4.9? Around 4.9. If I consider this as five, and this as 25, then it will come to
around 55. Meaning the area will be less than 55. The area calculated is slightly less than 55. 49 is way too
low, man. Slightly less than 55, so 53 is the only option. 64 is more, it's more than 55, so slightly less is only
53. So this is the answer you get. Okay , is it clear? Come on, tell me question number third quickly.
Greetings, I had my exam today, 87 total done, 22 done in Maths. Very good , Sahil. This is a very good thing. You
did 22 in Maths. Very good, man. Very good, right? Everyone, tell me the answer to this question number third. I
told you the level of the questions will be a bit better today. No Aditya Tripathi, if we assume 49 as an approx,
you would know, brother, how could it be 49? How could it be? Come on, tell me the answer to this. Look, it says
Sachin bought the first pen for ₹ 630 and the second pen for ₹ 722 respectively. Sachin bought the first
pen for ₹ 630 and the second pen for ₹ 722. Right? He sells the first pen at 70%profit but the buyer bargains for
the price and he has to offer a 9% discount. It says that the first pen, he had sold it at 70%profit. But right?
Meaning he sold it at 70%profit. But the person who was buying, he said, " Brother, please reduce it a bit, reduce
it a bit." So he gave a 9%discount. We are talking about the first pen. Right? Then, what was the profit percentage on
the second pen? 71%. So, you are asked to provide the value of the total profit. He is asking for the value of
the total profit made in both transactions. Right? Okay? So, look, first I will calculate the net profit.
Net profit of the first pen. For this, I gave you the formula x-y-xy/100, right? So, what is x for you? It is 70.
What is y? It is 9, so 70*9, that's right, divided by 100. How much is this ? 70 minus 9 is 61, 61, 9*7 is 63, so
61 and 63, how much will that be? If I do 6.3, how much will it be? If you subtract 61, how much will you subtract
from 61? 63, so how much will it be? Subtract 6.3 from 61, just subtract 6.3 . So that becomes 75, 10 minus 6 is 4,
and this 54.7%is the net profit on the first pen. So, that means I can calculate profit one, of what? 54.7%of
630, that is what I will do. That is what I will do. So, I brought this decimal point here. So let's remove the
zero. Now this has become 547. This has become 63. So I can make this 60 + 3. I can make it 60 + 3, right? I am telling
you this for calculation. What, 60 + 3? So 7*6 = 42, carry 4, 7*4 = 28 and 4, how much will that be? 32, carry 3, 7*5
= 35 and 3, that is 38 and this zero. Okay? Then it will go by three. 3*7 = 21, 3*4 = 12, 13, 14, 3*5 = 15, plus 1
is 16, how much is that? 4, 6, 1, 8 and this 9, and how much did this come to? Three. So how much will this come to?
Not eight, it will be seven. Sorry, it will be 32, right? Okay, so 344.61 something, right? We will do the
calculation like this. Second profit, how much is the second profit? 71%. On what, brother? We are getting 71%on 722
, right? 71%on 722. So, how much will profit two be for you? 71%of 722, solve this. 7*2 = 14, 7*2 = 14 and 1 is 15,
or I can do it directly, right? Yes, let's just do that. 7*2 = 14, 15, 7*7 = 49 and 1 is 50, 0, and this is your 722
, so how much will that be? 2 4 2 6 7 and 5 12, it will be 512.62. Absolutely 512.62, and what are you asked in the
question? Tell the profit of both. So, what will be the total profit, P1 + P2? P1 + P2, because we have to find the
exact value. Look at the options 54, 55 , 57, 56; we have to calculate it exactly. In this, I can't assume any
approximate value, as you are saying, we can't assume anything, neither can we look for any multiple nor anything
else. We will have to solve this. Okay? We have to solve this. So look, how much is this? Adding both of these, 2
and 1 is 3, 6, 12, 4, 2, 6 and 1 is 7, 4 and 1 is 5, and 5 is 857.23, the answer is coming. There you go, the
exact answer is here. Clear? We could not have done this by assuming any approximation. It had to be solved
completely because you have 1 hour, so you won't get it easy like that. Come on, tell me the answer to question
number fourth quickly. One question pie chart, two bar graphs, two SI, one triangle, one circle, two mensuration,
three trigonometry, two algebra, two time and work, two speed and distance, one partnership, one average. There was
no question from CI. One mixture. Okay? So it is correct for us. Questions on mensuration are definitely coming,
right? Radhe-Radhe Saurabh. Yes, questions on mensuration and questions on trigo, these were definitely coming.
Right? And there are a total of three in yours, right? One question of pie chart, two of bar graphs, so a total of
three questions were read by you. Right ? Come on, everyone will tell the answer to question number fourth.
Everyone tell the answer to question number fourth. This is easy. See, the question says, in an election between
two candidates, 15%of the voters did not cast their......vote. It says that in the election, 15%of the voters did
not cast their vote at all. Meaning they did not vote. Then, out of those who cast their vote, 10%of the votes
turned out to be invalid. Then it says the winning candidate, the candidate who won, got a total of 8262 votes, and
he got 72%of the total valid votes. That means the value of 72%votes is given as 8262. You are asked to tell
the total number of valid votes. So brother, how will I calculate the valid votes? Hi Rajkumar. So how will I
calculate the valid votes? Brother, can I just say valid votes directly, okay? And this is 8262/72%. Meaning, I have
calculated it for the valid votes only. Calculated 100. Okay? This is the value to be calculated. 9*8 = 72, 9*9 = 81.
One 6, 9*1 = 9, 9*8 = 72. What is it going by again? 2*4 = 8, 2*4 = 8, 2*5 = 10, 2*9 = 18. So what will this go by?
4*1 = 4, 4*1 = 4, 1 9, 4*4 = 16, three 0, 4*7 = 28, 4*5 = 20. So these 11475 were your total valid votes. It is
asking for valid ones. It is not asking for the total; don't just do x*85/100* 90/100, no, it is asking you for valid
votes in the question. Is the valid vote clear for everyone? Come on. Tell me the answer to question number five.
Tell me quickly. This one is easy. I just told you the formula to calculate net profit. Here you have been asked
for the actual profit. It says a retailer, there is a retailer. He has marked his price, according to which he
gets a profit of 21%. If he allows a discount of 12%on the marked price. Then it asks you what the actual profit
on the article will be. You have to tell this. Tell me. Everyone will tell the answer to this. See, I just told
you the formula to calculate net profit . What was the formula I told for calculating net profit? x-y-xy/100, so
how much is x? 21-12-21*12 divided by 100. So 21 minus 12 is 9, minus 12*1 is 12, 12, 24 plus 1 is 25, so 2.52; this
becomes 9 minus 2.52, which is 6.48%. Your net profit has arrived, that means 'D' is your answer. That was all you
had to do, where was the problem, tell me? Where did you face a problem? I just told you this formula, that
whenever you calculate net profit in such questions, what formula will you use? Profit percent minus discount
percent minus p*d/100, this is the formula, right? This formula is clear, okay. Let's move to question number six
. Hey, it won't be C. It was D, 6.48 was D. Everyone will tell me quickly. Ma'am, for Mains, is self-study, a
batch, or revising old notes better? Revision of old notes, self-study, and practicing questions is enough. Sahil.
Come on, this was a question of seconds , brother. What is to be done in this? What is to be done in this? What to do?
It says Mehul bought a car for 56,000. Then he got it renovated and after that he sold it for 6,400. He had bought it
for 5,600. Sold it for 6,400. Then you were asked, what is the percentage increase in price? That is exactly what
needs to be answered, brother. Look here, cancel out four zeros with four zeros. 8 = 64, 8 7 = 56, so it went
from seven to eight. Meaning C and SE, that is your CP and this is your SP. How much profit was made? One, so 100
divided by...how much does that make? That comes out to 100/7%. The answer was B. That was an easy question. There
was no difficulty in this. Alright, tell me this one. Length of the bridge. It's a train question. It's a train
question. Everyone will answer. Yes, absolutely. Surya, it was not C. It was B. Surya, it was not C. Its answer is
B. Its answer is B. It is B. And everyone, like the session, guys. You are not liking it. There are absolutely
no likes coming in. Give the answer. See, there is a 220-meter long train that crosses a single post in 11
seconds. A single signal post means its length will be negligible, so we can definitely calculate the speed of the
train; the speed of the train will be found from this, okay. Then it says that this same train, the same 220-
meter long train, crosses a bridge in 18 seconds. So, you have been asked for the length of the bridge. So first,
let's find the speed of the train. What will you divide 220 by? 11, so how much is that? The speed came out to 20
meters per second. Now you have the length of the bridge, let's find the length of the bridge. Let's find the
length of the bridge. The train's length is given, equals to what will this be? 20 is the speed. How much time
is it taking to cross? So how much is that? 18*2 = 36, so 360-220. How much will that be? The length of the bridge
will be found. How much did it come out to be? 6 minus 2 is 4, 3 minus 2 is 1, so your 140-meter long is your...Bridge
. This was the question. Right? This was the question. Anyone who hasn't seen the train questions, go check the
Arithmetic 30-Day Marathon session once . It covered train questions very well for you. Right? Alright, tell me
question number eight quickly. Question number eight. Tell me. Good evening, Saurabh. Ma'am, I have spent 100+ hours
on geometry. The questions that came were also at a zero level. No, number of common tangents when two circles
intersect? A question on the perimeter of a triangle came, I mean, the questions were just easy, right? Hi,
Pawan! Are you from Andhra? Welcome to Mentor Mind YouTube channel. Come on, everyone quickly like the session, okay
? Tell me the answer to question number eight. It says that a train has an average speed that is 50%faster than a
car. Both start from a point at the same time and go in the same direction, and they reach point B at the same time
. Meaning they leave point A at the same time. They reach point B at the same time. Okay? So it says which is 75
km away from A, meaning the distance between A and B is 75 km. Okay? It says that on the way, the train stops for
12.5 minutes. The train stops, right? Maybe some station came up. It must have stopped. Okay? Then it asks you
for the speed of the car. The speed of the car is asked from you. First, look at what is given. 50%faster than a car.
The speed is given for whom? This is your car. This is the train. Right? How much speed is given? It says that the
train is what? It is 3/2. Of what? The car. So, its ratio is two and this one is three. This is the speed ratio. Then
you can tell me the time. If you have the speed, because you know the formula distance = speed*time. So, the
relationship between speed and time is inverse. So if this speed is given, the ratio will be reversed to 3: 2. Now,
this one unit is your difference. Now, the value of this one unit is stated as 12.5 minutes, which is what it stopped
for. 12.5 minutes that it stood at the stop. Right? 12.5 minutes that it stood at the stop. So, tell me what the speed
of the car will be. You will say, multiply by 12.5. How much will it be? 12*3 = 36 and how much will this be?
37.5 minutes. It's 37.5 minutes. Now, what will I do to change this into hours? Well, we will change this into
hours. 375/10, remove this point and multiply by 60. Okay? What is this going by? 15*2 = 30, 15*5 = 75, 15*4 =
60, 5*5 = 25, 5*2 = 10, meaning it's taking 5/8 hours, for whom? For the train to reach. Okay? To cover how much
distance? 75 km, so we can state the speed. We can calculate the speed. Can we calculate the speed or not, brother?
Go ahead and calculate the speed. What will the speed be? You would say 75 km, reached in 5/8 time, so 5 will be how
much? 15, 15*8 = 120 km/hr, whose speed is this that you got? Whose speed have we got? Whose speed is it? This is the
train's. We calculated the speed of the train. Right? No. We calculated the speed of the car, brother. Calculated
the speed of the car. What was asked in the question? State the speed of the car. Right? The car's, because it was
taking 12:30 minutes, it stood still, brother. It was taking 12 minutes. So brother, how much did it become? 120 km
/hr is the speed you got. Is that clear , ma'am? I had my SSC exam today. It went really badly. What happened?
Saurya, Sariya, Sariya. What happened? Tell me. Meanwhile, solve this question . I'll ask what happened to them? What
happened? Was there no time management? Tell me the answer to question number ninth. Meanwhile, you, Hi Samendra
Kumar, everyone tell me the answer to this. Look, how much is sin 60? How much is sin 60, brother? It's root 3/2,
right? Plus, what is tan 30? It is 1/ root 3. Cos 45 is 1/root 2. So take the LCM, what will it be, 2...It will be 6.
Exactly, this will become what? Two got cut. So it will be 3 root 2. Absolutely . Plus this will become how much? 2
root 2 plus this will be how much? 2 root 3, so you can say 5 root 2 + 2 root 3 came. Divided by 2 root 6, now
normalize this 6. Multiply by 6 on top as well and multiply by 6 below. Meaning do it on both sides. So how
much will this be, brother? 5*2 = 10, so 10 root 3 + this will be 3. So 3 and 2 = 6, 2 divided by 2*6, now see what
it's cutting with, it's cutting by two. 2*5 = 10, 2*3 = 6, so what is this, 5 root 3 + 3 root 2/6, now look at the
options, 5 root 3 or 5 root 2. Man, there is 5 root 3 here, and 5 root 2 here. Now these two options are left.
Okay, so the denominator in the division is six, so this is your option , this is the option. Where was the
difficulty in this? Tell me, where did you find it difficult? Right, where was the problem? Alright, Answer to
question number 10, tell me the answer to question number 10. Greetings from the sacred land of Maharashtra.
Greetings Ashok, greetings, greetings. Yes. What should I say? GS solution. Sahil, for what? GS solution for Mains.
Man, it is unpredictable. What should I tell you now? Brother, those 75 questions that are given, look on any
app, there is a Testbook app, questions must be given there. Right? Do them. Do them. Yes, I explained all of this to
you Arya, I explained that you should manage your time and the rest will be taken care of. Manage your time,
otherwise the paper will be spoiled. This is what I have been explaining to you children repeatedly, right? We look
, we have to divide this. So when I divided 143 by six, the remainder came out to be: 6*2 = 12, 2, 3, 6*3 = 18,
the remainder is five. Into, divided this by six, look, three and six will be divided, right? So this 6*2 = 12, 12
, 2 and 1, 6*3 = 18, the remainder is 3 . Into, 6*2 = 12, 6*2 = 12, a remainder of one came. Now multiply them, do 15
15/6. 6*2 = 12 6*2 = 12, so what is the remainder of this? Three. This is your answer. This is what was asked. When we
divide, what will be the remainder? What will be the remainder? That is all that had to be done. Right? Let's move
on, tell me the answer to question number 11th. It is an average question. Quickly, not salary, they asked. They
asked for the manager's salary. Everyone will tell the answer. What will you do with this? Right? What will
you do, brother? It is a very easy question. There is no issue at all. Tell me how much it changed and
everyone should like the session quickly. Tell me the answer to question number 11th. Yes, dangerous, dangerous
unit digits. Okay. Oh, the 2000 RRB JE was hard. Okay, Yes, it can be done with a single digit. How will it be
done with a single digit? I didn't understand. Tell me the answer to this. It says that the average salary per
month of 23 employees is how much? If a manager is added, and the manager's salary is added, by how much does the
average salary increase? To 4300, meaning it was already 4000, brother. Right? I have been asked for the
manager's salary. It was 4000 before. By how much did it increase? It increased by 300. And how many new
employees are there? There are 31. So how much will it be? 4000 plus 3*1 = 3, 3*3 = 9, 9300, add this up. How much
will it be? 300, 9, 4, 1300. 13300, what is that? This manager, 13000, sorry, 13300, what is that? That is the
manager's salary. Meaning option D, is that clear to everyone? Alright. Okay. Tell me the answer to question number
12. Greetings from Uttarakhand, namaste . Namaste brother, namaste. Rahul ji, namaste. Oh, that question could have
been done using the single unit digit. Okay, okay, alright, I understand. Danger, danger, how did that 300 come
about, because 4300 becomes your new one. What was the question saying about 4300? One second, the question was
saying that the salary increased to 4300. Right? The salary increased, the average salary increased to 4300. So,
brother, it became 4300. So, I need to see what the increased average is, right? So I have the old average plus
the increased average, that multiplied by the total new employees, will give you the new manager's salary. Okay? It
calculates the salary of the person who was added. Clear? Okay. Tell me, did everyone get the answer? Did everyone
get the answer? Look, 3x + 4*8, what will you do with this, brother? Tell me . Did everyone finish it or not? So
look, 3 and this will be 3x + 32/9. 32/9 and this x/3-1, so should I take it over there or bring it over here? So
how much will this be? 3*3 = 9, 9 minus 1, 9 minus 1, you will say how much, 8/ 8/3x, and how much will this be? Going
over there it becomes minus, so 9 and 32 will be -41/9, three cut with three, so the value of x came out to be -41/24
, that is what was asked in the question. Did everyone get this same answer? Did everyone get this same
answer, right? Okay, tell me the answer to question number 13 quickly. I will tell you a method for this. Naveen
Phogat, hello! Hello, how are you? Okay , tell me question number 13. There is a trigonometry identity, I will tell
you that one. What does that identity say? I won't prove it now because the lecture will end. It would take a lot
of time to prove it. But I will tell you the identity that 1-cosθ/sinθ*1 + cosθ sinθ = 1 is true. This is the
identity you want to state. Right? Meaning, this implies that both of these are reverses of each other. So,
what does 1-cosθ/sinθ become for you? It becomes the reverse. Divided by your sinθ goes up and this 1 + cosθ part
gets flipped. It becomes reversed. Right? Meaning, this thing is equal to yours. So now, tell me, the value of 1-
cosθ/sinθ is given as 1/5. So what will its value be? It will be five. There you go, it's five. That’s all
you had to do. Right? You didn't even have to solve it. If you remember this identity, you will be able to do it. If
not, it will take time. Okay, the income, expenditure, and savings question is on your screen. Tell me its
answer. Right? Everyone will tell the answer to this quickly. For question number 14. Look, in question number 14,
it says the annual income of Anand and Bharat is given. Bharat's. I am not saying Bharat (India). The ratio of
Bharat's annual income and Anand's income is 3: 5 and their annual expenses ratio is how much? 1: 3, if
both save ₹ 10,000 at the end of the year, then tell Bharat's annual income. You have to tell Bharat's annual income
. Meaning, all are multiples of five, brother. Tell me. No Rahul, there was no class during the day. I had updated
it on Telegram, right? Tell the answer. Exactly, look, Anand and Bharat, what is the ratio of income given? 3: 5 And
what is the ratio of expenditure given? 1: 3, but what is the ratio of savings, brother? 10,000 and his too is 10,000,
right? So cross-multiply these two. 3*3 = 9 minus 5. 9 minus 5 is 4, and what is the value of 4 units given to you?
Three and one, this will be how much? 2 *10,000, meaning 20,000 is given to you . Okay? So what will the value of one
unit be? 5,000. Meaning this is going to 5,000. So what have you been asked? The value of B has been asked. The
value of B has been asked. Bharat's value has been asked. So you will say 5 *5,000, how much will you get? 25,000.
This is his income that came out. That is the income that was asked. The income is just 25,000. There was
nothing to do in this, right? This was a ratio question. It was absolutely easy. It's a ratio question because
income, expenditure, and savings all fall under the topic of ratio and proportion. Alright, give me the answer
to this, question number 15. Question number 15 says that the present population of the city is 60,000. If it
is given that the present population is 60,000 and it has increased by 25%every year, then tell me what the population
was 2 years ago. What was the population 2 years ago? You have to tell me this. Tell me, what will we do?
And everyone please like the session. Look, it's 60,000, so can I say 25% means, what would you say for 25%? 1/4,
so if I say that it was x two years ago , then it increased to 5/4*5/4. It is given equal to what? 60,000. Right? It
is given as 60,000, isn't it? Now, if you want to solve it, you can, or you can just do this. 4*16*6 = 96, so how
much will this be? The value of x is 96,000. And this one zero. 9600/25*3 = 75, 6 minus 5 is 1, 9 minus 7 is 2, 0,
25*8 = 200, okay, 25*4 = 100, and here are two zeros. 38,400 was the initial population of the city, whatever your
city is. What was the population 2 years before that? 38,400, that was your question. Is it clear to everyone?
Has everyone understood? Alright, question number, hey where did 16 go? Tell me question number 17. Question
number 17's answer, everyone will tell the answer to question number 17. Everyone will tell. Answer to question
number 17. No, no Rahul. It is not 3840 . The answer was 38,400. It was 38,400. Did I write it wrong? One second, did I
write it wrong? 25*3 = 75, one, two, one, 25*8 = 200, right? It was 21, right? 25*8 = 200, so 10 remains, zero.
Yes, it is 38,400 only, right? It is 38,400 only, it's not 3840, look carefully. Okay? Tell me its answer.
18.75%loss. Okay, Okay brother, let's see. Look, it says Ankita sold three toys, the first one she sold for 1500
and earned what profit? 25%. She sold the second one for 2800 and incurred what loss? 50%. And the third one he
sold for 3500, and how much profit did he make? 25%. So we can find CP1. How much will CP1 be? You will ask, whose
value is this 1500 given as? 25%means 1/4, that is, the value of five is given. 5*3 = 15, and if I multiply 3 by
4, I will get 1200. Exactly, it came to 1200. Similarly, I will find CP2. How will I find CP2? What happened with 50%
? There was a loss, meaning 1/2, so if this is 2800 you have, what will be half of it? Since there was a loss,
what must have been the original CP? It must have been 5600. We can find CP3 as well. We can also find CP3. How? Well,
he sold it for 3500 and made a 25% profit. Meaning 5/4, so the value of five is 3500. Then we will state the
value of four. Meaning how much will it be? 7*4 = 2800. What is the total you have? 0, 0, 8, 2, 10 and 6, and this 5,
3, 8 and one is 9600, that is the CP you got, the total cost price you have, right? Total cost price is 9600. How
much will be the total selling price? Since you have been asked to state the total profit and loss percentage, you
will tell how much this total SP is? Add 1500 and 3500 and 2800. How much is it? 3, 4, 5 and two is 7800, 7800 it is
, okay. Now look here, cut the two zeros, and what will this go with? Will this go by four, by four? No, it will
go by six, right. 6*1 = 6, 6*3 = 18, 6* 1 = 6, 6*6 = 36, meaning what is the ratio of CP and SP? 16 and 13, meaning
how much changed? 3/16*100, so what does 100/16 mean? 6.25. 6.25 means if I multiply by three, then 25*3 = 75 and 6
*3 = 18, meaning there is an 18.75%loss . It was in minus because three came in negative. Since three came in negative,
D will be your answer. It will not be profit. Clear, clear? Let's go. Tell me question number 18 quickly. Question
number 18, the questions are very difficult today. I am assuming it must be taking you some time to solve the
questions. It must be taking a little while. Right? No problem. Give me the answer. Everyone, tell me the answer to
question number 18. Jai Hind Suraj, look at the answer to question number 18. Abhi completes a task in 50 days,
and Varun is 25%more efficient than Abhi. It says that both work together for 8 days and the remaining work is
completed by Charu alone in 6 2/5 days. So, you are asked in how many days will Varun and Charu together complete 75%of
the total work? This is what is being asked of you. Right? So look, Abhi worked for 50 days. But it says that
Varun is 25%more efficient than whom? Abhi. That is, their efficiency ratio is 5/4. So I can calculate the total
work, how? 50 and what is Abhi's efficiency? Four. So, let's assume the total work is 200. I have 200 as the
total work. Okay? Now it says that Abhi and Varun worked together for 8 days. That is, they worked with an efficiency
of nine for 8 days, meaning 72 work was done. So, out of 200, 72 is gone, how much is left? Eight, 9 minus 7 is 128
left. Now, the 128 work was done by C alone in how many days? 6 2/5, that is 5*6 = 30 plus 2 = 32/5. Should I do 5?
Absolutely. So 4*2 = 8, 4*3 = 12, it goes four times. So what is his total efficiency? 20. C's efficiency is 20,
Varun's efficiency is 5, it asks for 75 %in how many days. So 75%of 200 is 3/4. With what efficiency? 20 plus 5, 25. 25
*8 = 200, 4*2 = 8, how many days did it take? 6 days. There is the answer. Tell me, how long did it take? Hey, how will
it be D? How will it be D? Six, Rahul, D will not be the answer. Six will be the answer. Clear? Come on, don't look
at the question. I will write it down for you. This is the question given: 4 ^ (2x-16)*4 ^ (x-5) = 64. That is your
question. You have to tell me the solution for this. Right? This is the question you have. This is the question
, don't look at that one. You have to give the answer to this. Come on, tell me. No, Rahul, D is not right for that.
It will be six only. Everyone, please like the session once. Those who haven't liked it yet, tell me quickly.
Tell me the value of this. The value of x is asked here. Can't you say that the base of four is the same? So if the
base is the same, what will happen to the powers? They will be added. Meaning , you can write 2x-16 + x-5. And this
four, this is 64. Whose cube is 64? It is the cube of four. So, you have to make the base the same. So, 4 cubed,
how much will this be? 2x and this 3x- 21 = 3 because if the base is the same, the powers will be equal. The powers
will be equal, right? So, what will the value of x be? 21 and 3, 24/3, meaning eight. You have the answer as eight.
Clear? Very good. Everyone got eight. Very well. Let's move to question number 20. Tell me, brother, question
number 20. Everyone will give the answer to question number 20. Everyone will tell the answer to question number
20. Tell me the answer to question number 20. Look, A, B, and C all work in 15, 12, and 18 days respectively. B
and C started the work and they worked for 6 days. After six days B left. After 6 days B left and A joined. So
it's asking, how many days was the total work completed? In how many total days was the work completed? So look,
brother, first calculate the total work ; A did it in 15 days, B in 12 days, and C in 18 days. What will the total
be? It will be 180 as the LCM; 3*5 = 15 , 3*4 = 12, 3*6 = 18, so three is already there. Okay? After that, five,
15*3 = 15 and this 4, 15 and 4 is 60 and this three is 18, so 180; how much will this go? 15*1 = 15, 15*2 = 30;
this 12*1 = 12, 12*5 = 60 and this 10, this is their efficiency. It says that then B and C worked together for 6 days
. After 6 days, B left. So B and C worked for 6 days. Meaning 25, right? 25*6, how much work was done? 150 was
done. Now how much is left? 30 work is left. Now, the 30 work that is done, what is it saying? That A joined. With
whom? With him, with C. So how much work is he doing? 12 and 10, 22, meaning 11 and this 15. So the work is
being done in 15/11 days. But it is asked, how many total days will it take ? Brother, 6 days were taken by B and C
earlier. Right? Then how much are A and C taking? 15/11, so how much will that be? 66, 66 and five, how much is 15? 71
and how much is this? 10, 81, the total work is done in 81/11 days. This is your answer. Did everyone get A as the
answer? Did everyone get A as the answer? Tell me. Everyone got A. Okay. Quickly tell me the answer to question
number 21. The answer to question number 21. Look, a train is traveling at a speed of 60. It crosses another
train in the same direction, whose speed is given as 24. It is crossing in 30 seconds. So, you have to tell what
the sum of both trains is. Tell me, and everyone please like the session. Right ? Everyone please like it once. Alright
, look, one train is going at 60, one train is going at 24. So when both go in the same direction, the relative
speed is subtracted. And when they come from opposite directions, meaning coming towards each other, the speed is
added. So, 60 minus 24. The sum of both trains is asked, meaning the length of train one plus the length of train two
is asked. What is the difference between both their speeds? 10 minus 6 is...6, 5 minus 2 is 36 kilometers per
hour, and I need the answer in what? Meters. So I will convert this to meters per second. So 5/18, and in how
many seconds are they crossing each other? In 30 seconds. Here you go, 18*2 = 36, 5*2 = 10, and this is 300 meters.
So the sum of both trains you have is how much? It is 300 meters. Do it carefully. Don't write kilometers by
mistake. Do not write kilometers, clear . Alright, tell me the answer to question number 22. Everyone will tell
the answer to question number 22. Quickly tell the answer to question number 22. Tell me the answer to
question number 22. It says the length and breadth of the rectangular park are in the ratio of seven and three. What
is the perimeter of the park? It is 21,000. It is asking you to tell the difference in length and breadth,
meaning a multiple of four. How many multiples of four are there, brother? Look at this. There are two options
that are multiples of four, A and D. Right? Apart from that, what can you check? You can check for a multiple of
seven, so option A will be it. That would be your answer, right? Okay, Saurabh Azamgarh. That would be your
answer, but let's calculate it. They are saying the ratio of length and breadth is given as 7: 3, so what will
be the perimeter? 7, 3 is 10, times 2, so the value of 20 is given to you as 21,000, right? What do you need to find
? Their difference. What is the difference? 7 minus 3 is 4, so you need to find the value of 4. So, 21,000
divided by 20 times 4, so 4*5 = 20, 21,000 divided by 5 equals 4,200; that is the difference between their length
and breadth. This is the difference between length and breadth, that is what the question was saying. Clear? It
was easy, right? Yes, Ashwini, there are two multiples of four. There are two multiples of four, A and D are your
multiples of four. But it also talks about seven, right, 21,000, so you can also check for a multiple of seven.
Then out of A and D, only one is a multiple of seven, which will be your answer. Right? You can check that too,
it is your choice. Alright, let's solve question number 23. Question number 23 is about Time and Work; we have asked
so many Time and Work questions today, this is the 22nd or 23rd question. Seven questions are still remaining,
right? Seven more questions are left. I will finish them quickly. I will do it quickly now. Right? I won't drag it out
. I won't make the class too long. Don't worry. I will tell you quickly. Everyone, answer this. Everyone, tell
me the answer to this. For question number 23. Alright, there are two persons, A and B, both are working. A
takes 60 days. B takes 40 days. Okay? Both started the work together. But A left after some time and B did the
remaining work in how many days? He did it in 10 days. So you are asked, A left after how many days? After how many
days did he leave? That is what is asked of you. Right? So, first let me calculate the total work. A takes 60
days. How many days does B take? 40. The total work will be 120. This is two and this is three. Meaning now it says
that B did the remaining work alone in 10 days. So, B worked with an efficiency of three for 10 days, how
much work did he do? 30, meaning 120 minus 30 equals 90, so the 90 units of work was done by A and B together. With
what efficiency? With an efficiency of five, so 90 divided by 5 equals 18 days . So, how many days did A work for? 18
days. After how many days did he leave the work? He left after 18 days, man. That was all that had to be done. Just
that much had to be done. It won't be 15. It won't be 15. MS Dhoni, it won't be 15. Clear? Okay, tell me the answer
to question number 24 quickly. You have been asked for the average age of all the persons. Tell me, what will be its
answer? What would you say for this? Tell me quickly. Look, the question says the average age of 35 people is
given as 40. Five new people were added . Okay? Whose average was how much? 35. So you have to tell what the average
age of all the persons will be, of all the persons. So look brother, 40 was your old average already. Okay? Five
people were added, right? Five people added, so you will subtract, right? Because you have to find the average
age of all the persons, so we will subtract. Absolutely, into how many did you have, brother? From 40, 35 went
away, how much of a decrease was there? It was of five. Divided by how many were there in total before? How many
were there in total before? How many were there in total, brother? There were 40, right? Here you go, 5 was 40,
so how much did it become? 40 minus 5/8 , that is 320, 320 minus 5, 320 minus 5 , how much will it be, 315? You will
divide 315 by 8. Calculate 8. 8*3 = 24, 8*9 = 72, and this is 3/8 years. Meaning, this will be your new average
of all persons when these five people are also added. If they hadn't joined, or hadn't gone, this would have been a
plus. Okay, it would have been a plus. Clear? Okay. Absolutely very good brother, very good. Everyone is
answering, it feels very good. Okay, tell me question number 25. Two equations will be formed. Two values of
x are given. One is -1 and one is -2. Meaning, one time you have been given the value of x in the quadratic
equation. -1 and -2, meaning you will put two values. From here you will find the values of p and q. Then put them in
the equation that is given. This is a basic concept question. Meaning, this is the same basic question we've been
reading since childhood. Right? No need to apply any concepts or anything in this. Tell me, everyone will tell. And
everyone please like the session. Everyone should like it too. Right? Those who are not liking it, please
like it. First, what should I do with the value of x? -1, so how much will this become? 3-p + q = 0, meaning if I
write p-q, it will be 3. It definitely will. Similarly, if I do -2 once, then -2 squared is 4, 4*3 = 12, so 12-2 p +
q = 0, meaning if I do 2 p-q, what will it be? It will be 12. Now, if I subtract this equation from the other
equation, what do I get? q will be canceled by q. 12 minus 3 is 9. Now, you can find the value of q. When this
is nine, if we bring three to this side , what will we get? It will be six, right? Now we have to state its value.
We need to state 3p-2q. You can tell me , right? 9*3 = 27, 6*2 = 12, what did we get? 15, that is the answer you got.
How long did it take? How long did it take? Tell me. Yes, absolutely, keep it happy. Right? Look at it. Clear? Let's
see question number 26. The population of a city increases 5%annually in a compound manner. The population of the
city increases by 5%. But it increases compoundly. Compoundly means it is growing at a compound rate. Okay? That
it grew in the first year, and then over the grown amount, it increased further. Okay? So, the present
population of this city is 9351, so it says the present population is 9351. It asks, "The population of the city 2
years ago was", so you have to tell what the population was 2 years ago, right? Tell me what the population was
2 years ago. Tell me quickly, everyone should tell me quickly. Come on, very good MS Dhoni, Saurabh, very good. Look
, it says it is 9351, right? If I assume, if you ignore this population, if you look at the principal and amount
, it is increasing by 5%annually. How much will it be in 2 years? It will increase by 10.25. 10.25, and whose
value is given here? The amount is given, the total increased value is given. Meaning, whose value is 9351?
It's 110.25. It is 110.25, isn't it?* 100, you have to find the population of 2 years ago. Right? We will find the
population of 2 years ago. What should we do? Now look, if I remove a point. I will remove the point and add zeros
there. If I remove this point, I will add zeros. Look, 25*4 = 100, this 25*4 = 100, this zero, 25*4 = 100, 25*1 = 25
, so it goes 441 times. It will go on two. Because 2*4 = 8, 2*4 = 8, how much will this two be? Subtracting from 30,
so 10 minus 2 is 8, 12 minus 8 is four, and then this five. Again it will go on one, so 441, five minus one is four. It
will go on one again, right? So how much did it come to? How much did it come to? You would say 4*1 = 4, 4*2 = 8
, 4*2 = 8, 88000 400, it was 2 years ago and 2 years later when it increased by 5%compound interest, what did the
population become? It became 9351. That was your question. Clear? Very good, everyone got this answer. Let's move
quickly, only four questions left, then it will be finished, right? Tell me the answer to question number 27 quickly.
You are given a triangle ABC, AB and AC are equal, and ACD you have is 95, and D is an outside point. It is an
extension of what? BC. So it is asking what angle BAC is equal to. This is what is being asked in the question.
Right? Danger danger, how did this 110.25 come? Look, look, you must have read about 5%compound interest. When
the table was taught, for two cycles of 5%, if you do a + b + ab/100, it becomes 10.25 for 2 years. Okay? What
is this that you have? This is the increased number you have. Increased by how much has it increased? This has
increased. But what has it become after increasing, brother? I say that increasing from the previous one, look,
I mean to say that I will calculate 5% for 2 years. So a + b + ab/100, although I have taught this in the
table that you have to keep them memorized. So 5 and 5 10, meaning a and b you have both as five here. Right? So
10 and this 10 and how much will this be? 25, 25/100 is 0.25, this 10.25 has increased, right, it increased by 10.25
. This has increased by 10.25. Right? So brother, you must have had 100% initially, then it increased by 10.25%.
So how much did it become? 110.25%, this is the increased thing. Right? It is after 2 years. So 2 years ago, it
was 100%, right? So, I calculated the value of 100%in this way, Danger. Clear ? Okay? Did you understand? Let's solve
this question now. Right? Look, there is a triangle ABC. Here you have ABC, A B C, it says BC is extended up to where
? Up to D, then ACD is 95. So tell me, how much will this be? You will say it will be 85. Because 180 minus 95 is 85,
and if AB and AC are equal, then both angles are equal, so this will be 85. And what is the sum of a triangle? 180,
so both are 85 and 85, then what will this angle be? These are 85 and 85, making 170. 170, 180 minus 170, how
much is left? 10 °, what is the question asking? Angle BAC, meaning how much did this come to? It came to 10 °
. The answer is D. Did everyone get D? No, it wasn't a discount. Danger, it wasn't a discount. That was based on
your population. I had given you the formula for that. Right? I had told you the formula. Clear? Come on, everyone
will give the answer for question number 28. Tell me quickly. 28 is a concentric circle. Everyone will give
the answer for question number 28. Concentric, the radii of two concentric circles are 34 cm and 50 cm. A and D
are two points on the larger circle and B and C are points on the smaller circle. Okay? ABCD is a straight line
and the length of BC is given as 32. You are asked for the length of AD. Good evening, Saif Ali. Hmm, let me
explain. Look, these are two circles. One is this big circle. This is your small circle. Okay? Clear? No issues or
problems up to here. This is a straight line. Right? This is A. This is B. This is C. This is D. The length of BC is
given to you as how much? 32. Meaning this is 32. So here is your center. So from here to here is your smaller
radius. And this is your larger radius. Right? This is the larger radius. Clear ? So from here to here, tell me, it
will bisect it in the middle, right? So this becomes 16. This will be 16. Exactly. So this radius, the smaller
one, what is given to you? The smaller radius is 34. The larger one is how much? 50. So I know that for the 34 and
16 ratio, to find the third side, I should first write 17 and 8. Right? But I know that the third one is 15. Right?
Because I know a triplet. What? I know the 8-15-17 triplet. Right? If I know this triplet, and I multiply them both
by two, then 17*2 is 34, 15*2 is 30, and 8*2 is 16; so 16 is a side and 34 is also there. So what will this side
be? Meaning, if I assume O and M, then what will this be? How much will this one be? OM will come out to be 30. It
is 30, okay. Now let's look at this larger triangle, which one is it? O's hypotenuse is 50, okay. Is it a
hypotenuse or not? It is a 50 hypotenuse, right? So look, this is 30, and I am saying this is 50, and this is
30 again. This is 50. You have to find AM. To find AM, you can either calculate it using the formula 50²-
30² = AM², you can find it that way too. If you don't want to calculate, look at what you do. Reduce the ratio,
and you know there is a 3-4-5 triplet. 5*10 is 50, 4*10 is 40, and 3*10 is 30, so this 30 is given. 50 is given. So
how much will AM be? From here to here it will be 40, right? When AM is 40, then how much will AD be? It will be
double. What will AD be? Double of AM, which is 40*2 = 80 cm, this is your answer. Is this question clear? Is it
clear? How will you solve it? Is it clear? Tell me. Did you understand? Okay. Question number 29: The average
monthly salary of a person. Solve the question. You guys solve it first. You guys solve it first. And whoever wants
the PDF should join Telegram. Whoever wants the PDF, they should join Telegram. I will upload the PDF there.
Right? Thank you so much, Piyush Yadav ji. Thank you so much. Yes, Rahul, it will happen tomorrow. It will happen
tomorrow, right? Let's go. Yes, look, " The average monthly salary of a person is 62000", it is saying that the
average, what is the average monthly salary of a person? It is 62000. "He also earns 6000 extra per month
overtime for 3 months", it means he also earns an additional ₹ 6000 per month overtime for 3 months. So, "Find
the overall monthly income of the person", it is asking to tell the overall monthly income. So 62000 is
already there, brother, 62 is there. Now look how much this is, 6000, how much is he earning for 3 months? He is
earning 18,000. By earning 6,000 extra per month for 3 months, he worked for 3 months and earned 18,000 by doing
overtime. If I have to calculate the overall monthly income. Need to calculate the overall monthly income.
Then brother, I have to distribute 18,000 over 12 months to see how much he is getting in 12 months. 6*2 = 12, 6
*3 = 18, that's done. If I add ₹ 1500 every month, if 1500 comes every month, then my salary will be equalized every
month. Right? So 62000 + 1500 equals how much will it be? 2 0 5 3 63500 is this your answer? C is your answer.
Clear, Namaste Ajgar, clear, everyone please like the session once. Yes, Danger class, a class has been
conducted based on compound interest. Right? Go and watch, the class has been done in the arithmetic section. Alright
, it's the last question. 30 is the last question. Tell me, what will be the answer to this? Tell the answer
quickly. Everyone will tell its answer. It's the last question. Everyone will tell the answer. No one will stop.
Everyone tell the answer to question number 30. This is a very easy question . It is truly very easy. Right? Don't
need to do any tricks. Don't overthink. Just read the question and you will do it according to the question. Everyone
will tell the answer quickly. Everyone will tell. No one will stop. This is the last question of today. I am
waiting for everyone's answer for this. Tell the answer to question number 33. Everyone will tell and I am waiting.
Tell me, what logic will you use to solve this? You don't have to use any such formula. Don't use anything. Just
tell me simply for question number 30. What does it look like to you basically ? What does it look like at first
glance? Tell me that. Okay. Sourav and Rahul are giving the answer. Okay? Will no one else give an answer besides
Sourav and Rahul? Come on, shall we stop the time? Ajgar has also given it. Aditya has also given it. MS Dhoni has
also given it. Come on, just four, how many children have given it? Only five children are able to give it. There are
23 students right now. Only five are answering. Why, guys? Everyone answer. Okay, Saurabh Kumar. Let's take a look.
It says sec theta-cos theta = 14 and 14 sec theta = x, then the value of x, meaning the value of x is given as 14
sec theta. Okay? So tell me, is this value of 14 given in the question, right? Can't I write it like this? So I
can do sec theta-cos theta*sec theta. Because its value is given in the question. It's not necessary that you
always put the variable's value as a digit. You can sometimes put the digit's value as a variable too, right?
Absolutely. So tell me, sec theta- subtract this. sec theta*cos theta will cancel out, because sec theta is 1/cos
theta, so this is -1. Now, whose formula is this sec² theta-1? tan² theta, because you have sec² theta-
tan² theta equals one. Right? So, bring this minus over here, and what does it become? tan² theta, so what is
the value of x? What is the value of x? You will say tan² theta. Here is your answer. Now tell me, only 29 questions
were done. How many were correct today? Right? A for Apple, Rahul. Okay, 18 questions out of 20, nice. Very nice.
Tell me, how many others were correct? Who got how many right? Everyone, answer quickly. I mean, not the answer,
but how many questions were correct. Right? Tell me quickly. Everyone will tell how many they got right. I am
waiting for your answers. Guys, I don't know how it was made. Right? A for Amazing Ma'am. Okay Rahul, Ma'am I just
arrived. At what time does it start here? Ravi Ranjan Kumar, your class starts here at 8:00. Your class starts
at 8:00. Right? Dheeraj 17, okay. MS Dhoni 20 out of, okay. Okay Rahul, fine , everyone tell me who solved them. We
attempted 29 questions, by the way, not 30 because question number 16 wasn't there, so I asked how many out of 29
questions were correct, right? Ma'am, I have my PET exam on November 1st, my score in math is low. How, how, Saif
Ali, how is it low, right? I searched all day long to find this question. Ma'am, you got 25 out of 30 today,
Aditya, were they easy questions? I personally felt they were a bit hard, and I thought you might have found them
tough today too because I’ve been giving you easy ones, what's today's date? It’s the 28th today, right? So,
up to the 31st...Tomorrow, I'll do some harder ones, and after that, I'll keep the questions easy because these hard
ones can lower your confidence, right? So, I won't do that, okay? For the third and second shift, danger, just do
all the ALP mocks I’ve provided, and for any tricks, math methods, or topics , I’ve held a 30-day session, follow
that, okay? Right now, Dheeraj, your series for CHSL runs during the day, right? Huh? Piyush Yadav, the class
timings are mentioned above. Where? On your home page, right? It is mentioned right there on the home page. You take
two live classes. From what time to what time is it, right? Yes Aditya, they were a bit hard. No problem at all
. But yes, you have to practice, man. There's no guarantee that they will always ask easy questions. We can't
guarantee that, can we? So, tell me, how do you find this question? How is the ALP series going? Do you see any
improvement now? Are the ALP students seeing any improvement? Are they seeing any improvement, tell me. And everyone,
please like the session, I get absolutely no likes, why is that? I would like to know, why? Tell me, why
is it like this? What exactly am I doing wrong that you all don't like the videos? Saurabh, you aren't able to
manage time in the exam because you feel you can solve the question, but what happens is you think you can, yet
you might make a calculation mistake, or you're taking too long, or your speed is slow; so work on these things.
Secondly, your concepts might not be clear for many questions, so you spend time reading them thinking you'll solve
them, then you realize you can't, then you move on; this is how time is wasted in the exam, right? Aditya, I will give
you extra questions, I promise, okay? Danger, ancient method, okay, ancient method. Look, whatever mock tests I
have conducted and the PYQ series I've done, nothing more than that will come. Do study the remainder theorem, okay?
Study the remainder theorem, study geometry, and read up on circles; you must read circles, it is very important
. Read up on circles, study triangle properties, and all these videos can be found in my section where the videos
are uploaded on YouTube, on this very channel, okay? Saif Ali, it feels hard because I am teaching you a few
questions at that level, which are unpredictable, so that if they appear, you won't panic, as these types can
also come. Otherwise, the paper is usually easy. It doesn't come hard, right? Yes, Saurav, there will be a
class tomorrow too. Right? There will be a class tomorrow as well. Greetings Sanjeev, Radha-Radhe. Ravi Ranjan ji?
For Railway NTPC, this is enough. It's enough. It's enough. Nothing more than this will be needed. And I will also
start an NTPC series. I will start one for NTPC as well. Right? I am doing well. How are you? Shall we meet again
tomorrow? Let's meet again tomorrow. Tomorrow we will meet in the afternoon. There was a power cut today. Because of
the power cut, I couldn't take the class. Tomorrow we will meet in the afternoon. So we will meet tomorrow
afternoon. At what time? At 1:00 PM. And I have told you that I have scheduled the classes on your channel.
Right? They are scheduled, and I will post them on your Telegram as well. By the way, what time the classes are held
, you should join the Telegram. If you want these PDFs, they will only be available on Telegram and nowhere else.
They will only and only be available on Ment and Mahi's Telegram. Okay? So everyone, please join the Telegram.
Alright, see you in tomorrow's class. Bye everyone. Till then, like, share, comment, and don't forget to subscribe
to the channel. Thank you. Jai Hind.
Use the successive percentage change formula: net profit = x - y - (xy/100), where x is the markup percentage and y is the discount percentage. For example, a 21% profit markup followed by a 12% discount gives a net profit of 6.48%, calculated as 21 - 12 - (21×12/100) = 9 - 2.52 = 6.48%.
First, determine the actual side lengths from the ratio and perimeter. For a ratio of equal sides:unequal side = 6:11 and perimeter 46 cm, the sides are 12, 12, and 22 cm. Then use Heron's formula: semi-perimeter s = 23 cm, area = √[s(s-a)(s-b)(s-c)] = √[23(11)(11)(1)] = 11√23 ≈ 53 cm².
First, find P(E∩F) using the formula P(E∩F) = P(F/E) × P(E). Then, divide by P(F) to get P(E/F). For example, with P(E)=0.4, P(F)=0.8, and P(F/E)=0.6, P(E∩F)=0.6×0.4=0.24, so P(E/F)=0.24/0.8=0.3.
First, find the train's speed using the time to cross a stationary object like a post. For a 220m train crossing a post in 11 seconds, speed = 20 m/s. Then, for crossing a bridge of length L in 18 seconds, set up the equation (220 + L)/20 = 18 and solve for L = 140 m.
Set up an equation using the ratios. For income ratio A:B = 3:5 and expenditure ratio 1:3, with both saving ₹10,000, multiply: A's income = 3x, expenditure = y, B's income = 5x, expenditure = 3y. Their savings equations give 3x - y = 10,000 and 5x - 3y = 10,000. Solving yields x = 5,000, so B's income = 5×5,000 = ₹25,000.
First, find the total work units (e.g., LCM of efficiencies). For example, if Abhi takes 50 days and Varun is 25% more efficient (ratio 4:5), total work = 200 units. After 8 days together (9 units/day), 72 units are done. If Charu completes the remaining 128 units in 6.4 days, her efficiency is 20. For 75% of work (150 units), Varun and Charu together have efficiency 25, so days = 150/25 = 6.
Express all terms with the same base. For example, 4^(2x-16) × 4^(x-5) = 64 becomes 4^(3x-21) = 4^3. Since the bases are equal, set the exponents equal: 3x - 21 = 3, solving gives x = 8.
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