Top JEE Doubts this Week

## a)0.668b)2.99c)0.167d)7e)none of theseCorrect answer is option 'B'. Can you explain this answer?

 Vineeta Shukla answered  •  5 days ago JEE
B

## a)2 - √3b)2 + √3c)16 - √3d)14 - √3e)None of theseCorrect answer is option 'C'. Can you explain this answer?

 Sanjeev Chalapandian answered  •  yesterday JEE
=2+√3/2-√3 +2-√3/2+√3 +√3-1/√3+1
=(2+√3)^2 +(2-√3)^2/2^2-√3^2 +√3-1/√3+1
=8+6/4-3+√3-1/√3+1
=14+(√3-1/√3+1)
=14√3+14+√3-1/√3+1
=15√3+13/√3+1
=(15√3+13)×√3-1/√3^2-1^2
=45 -15√3+13√3-13/3-1
=32-2√3/2
=16-√3

## a)510.984b)530.56c)520.47d)520.56e)None of theseCorrect answer is option 'E'. Can you explain this answer?

 Hari Sankar D answered  •  2 weeks ago JEE
Answer = 510.9908. Therefore option E

## Direction: Study the following question carefully and choose the right answer.If ACNE can be coded as 3, 7, 29, 11 then BOIL will be coded as ….?a)5, 29, 19, 27b)5, 29, 19, 25c)5, 31, 21, 25d)5, 31, 19, 25Correct answer is option 'D'. Can you explain this answer?

 Anirban Gupta answered  •  May 02, 2024 JEE

Explanation:

Decoding ACNE:
- The numerical values are obtained by assigning each letter a prime number starting from 2 (A=2, C=3, N=5, E=7).
- Then, the numbers are multiplied in pairs and arranged in a sequence (2x3=6, 3x5=15, 5x7=35).
- The final sequence is 3, 7, 29, 11.

Decoding BOIL:
- Using the same prime number assi
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## Let S be the set of prime numbers greater than or equal to 2 and less than 100. Multiply all the elements of S. With how many consecutive zeroes will the product end?a)1b)4c)5d)10Correct answer is option 'A'. Can you explain this answer?

 Kavya Saxena answered  •  Apr 28, 2022 JEE
For number of zeroes we must count number of 2 and 5 in prime numbers below 100.
We have just 1 such pair of 2 and 5.
Hence we have only 1 zero.

## Charlie and Alan run a race between points A and B, 5 km apart. Charlie starts at 9 a.m. from A at a speed of 5 km/hr, reaches B, and returns to A at the same speed. Alan starts at 9:45 a.m. from A at a speed of 10 km/hr, reaches B and comes back to A at the same speed. At what time do Charlie and Alan first meet each other? a)10 a.m. b)10:20 a.m. c)10:10 a.m d)10:30 a.m. Correct answer is option 'C'. Can you explain this answer?

Solution:
Let us first calculate the time taken by Charlie to complete the round trip from A to B and back to A.
Distance between A and B = 5 km
Charlie's speed = 5 km/hr
Time taken to go from A to B = Distance/Speed = 5/5 = 1 hour
Time taken to come back from B to A = Distance/Speed = 5/5 = 1 hour
Total time taken by Charlie to complete the round trip = 1 + 1 = 2 hou
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## 7.8 + 5.4 x 8.2 = ?a)52.08b)108.24c)48.05d)102.05e)None of theseCorrect answer is option 'A'. Can you explain this answer?

 Aarav Sharma answered  •  May 24, 2023 JEE
Multiplying Decimals

To solve this problem, we need to multiply 5.4 and 8.2. Here’s how we’ll do it:

Step 1: Ignore the decimal points and multiply 54 and 82.
54 x 82 = 4428

Step 2: Count the number of decimal places in the numbers we multiplied. There is one decimal place in 5.4 and two decimal places in 8.2, so we’ll add those together to get three decimal p
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## In a Country X, temperature decrease (in degrees) is linearly related to percentage increase in sale of water heaters and is given by the relation:ΔT= ky+5 Where,ΔT is temperature decrease (in degrees).y is the increase in sale of water heaters (in percentage).K is a constant.A temperature decrease of 10 degrees results in a 1% increase in sale of water heaters. What would be the percentage increase in sale of water heaters when temperature decreases by 15 degrees?a)1.5%b)2%c)2.5%d)3%e)3.5%Correct answer is option 'B'. Can you explain this answer?

 Palak Saha answered  •  4 weeks ago JEE

## A can do a particular work in 6 days . B can do the same work in 8 days. A and B signed to do it for Rs. 3200. They completed the work in 3 days with the help of C. How much is to be paid to C?a)Rs. 380b)Rs. 600c)Rs. 420 d)Rs. 400 Correct answer is option 'D'. Can you explain this answer?

 Kavya Sharma answered  •  Apr 11, 2023 JEE
C's 1 day's work =

1/3−(1/6+1/8)=(1/3−7/24)=1/24

A:B:C=1/6:1/8:1/24=4:3:1

C′sShare=1/8∗3200=400

## What is the name of the MR vaccine released by Indian immunologists to protect children against measles and rubella?a)RubixMb)MeasloGuardc)Immunellad)MabellaCorrect answer is option 'D'. Can you explain this answer?

 Anushka Choudhury answered  •  May 26, 2024 JEE
MR Vaccine released by Indian Immunologists
The MR vaccine released by Indian immunologists to protect children against measles and rubella is called Mabella.

Importance of the MR Vaccine
- The MR vaccine is crucial in preventing measles and rubella, which are highly contagious diseases that can have serious complications, especially in children.
- Measles c
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## a)62/3                                    b)6c)31/3                                    d)3e)None of theseCorrect answer is option 'D'. Can you explain this answer?

 Faizan Khan answered  •  Jun 21, 2020 JEE
On solving, we will get x = 3 or x = -2
Ignoring the negative value answer is 3.

## Direction: Study the following and answer the questions carefully:There are 8 members in a family namely A, B, C, D, K, L, M, N in which there are 2 married couples. Among the 8 members there are 2 lawyers and 2 artists. D is the daughter in law of M. L is the brother of any of the two artists. N, who is the artist, is the sister of A. No female is a lawyer. D is an artist. C is the husband of M. K is the only son of M. B is the lawyer and is the brother of C. A is the lawyer and is the son of K.Q. Which pair represents the lawyers?a)A,Bb)B,Nc)M,Ad)C,NCorrect answer is option 'A'. Can you explain this answer?

 Naresh menon answered  •  Feb 18, 2024 JEE

Analysis:

Given Information:
- 8 family members: A, B, C, D, K, L, M, N
- 2 married couples
- 2 lawyers and 2 artists
- D is the daughter-in-law of M
- L is the brother of one of the artists
- N, the artist, is the sister of A
- No female is a lawyer
- D is an artist
- C is the husband of M
- K is the only son o
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## How many moles of magnesium phosphate, Mg3 (PO4)2 will contain 0.25 mole of oxygen atoms?a)3.125 × 10-2b)1.25 × 10-2c)2.5 × 10-2d)0.02Correct answer is option 'A'. Can you explain this answer?

 Arjun Saini answered  •  Apr 09, 2023 JEE
Mg3(P04)→ 3Mg
→2 P
→ 8 mole oxygen
8 mole of oxygen - 1 mole Mg3 (P0)2
0.25 - ? 0.25/8 = 3 x 10-2

## P can do a work in the same time in which Q and R together can do it. If P and Q work together, the work can be completed in 10 days. R alone needs 50 days to complete the same work. then Q alone can do it ina)30 days b)25 daysc)20 daysd)15 daysCorrect answer is option 'B'. Can you explain this answer?

 Varun Kapoor answered  •  Sep 17, 2023 JEE
Work done by P and Q in 1 day = 1/10
Work done by R in 1 day = 1/50
Work done by P, Q and R in 1 day = 1/10 + 1/50 = 6/50
But Work done by P in 1 day = Work done by Q and R in 1 day . Hence the above equation can be written as
Work done by P in 1 day * 2 = 6/50
=> Work done by P in 1 day = 3/50
=> Work done by Q and R in 1 day = 3/50
Hence work done by Q in 1 day = 3/50 – 1/50 = 2/50 = 1/25
So Q alone can do the work in 25 days

## The number of proper subsets of the set { 1, 2 , 3 } is :a)7b)5c)6d)8Correct answer is 'A'. Can you explain this answer?

 Kritika Bajaj answered  •  Apr 28, 2020 JEE
Number of subsets of a given set = 2n
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