# RRB Practice Questions | Mathematics â€“ Day-11

Dear Aspirants,

Mathematics is a complex web. So only most of the applicant’s thought isÂ RRB Mathematics questions are tough to work out. It’s really not, to score the maximum mark in this section you need of regular practice on RRB Maths every day.

Start to practice Quiz forÂ RRB Mathematics section and reveal the answers with detailed explanation. We have taken much care on the explanationÂ part that to understand theÂ RRB Mathematics questions easily. TakeÂ RRB Mathematics quiz regularly to perform better onÂ  RRB Maths section without any hurdle.

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#### RRB NTPC Free Daily Quiz

1) 3 men can build a wall in 4 days. How many men are required to build 3 walls in 4 days?

a) 9

b) 5

c) 12

d) 16

2) A certain number of persons can do a piece of work in 30 days, but if there were 6 more persons, it would have been finished 15 days earlier. How many persons were there in the beginning?

a) 15

b) 6

c) 90

d) 30

3) A can do a piece of work in 10 days and B can do the same work in 15 days. If they work together for 4 days, then what fraction of work is left?

a) 2/3

b) 1/3

c) 3

d) 10

4) Pipe A can fill the tank in 24 hours and pipe B can fill a tank in 36 hours. If both the pipes are opened together simultaneously, then how much time will be taken to fill the tank?

a) 12 hours

b) 14 hours 24 mins

c) 24 hours

d) 13 hours 59 mins

5) John starts doing a project. After working for 10 days, he finds that only 2/5 of the work has been done. He employs Ram who is only 50% efficient as John. How many more days will John take to complete the job?

a) 12 days

b) 5 days

c) 10 days

d) 15 days

6) Arnav and Akash can do a piece of work in 8 days. Arnav alone can do the same work in 12 days. The number of days in which Akash alone can do the same work is?

a) 20 days

b) 36 days

c) 24 days

d) 48 days

7) A and B together can write a book in 24 days. If efficiency of A is double that of B, then in how many days A can alone write the same book?

a) 12 days

b) 14 days

c) 16 days

d) 36 days

8) A and B can complete a work in 12 days, B and C can complete a work in 15 days and C and A can complete a work in 30 days. A alone can complete the same work in how many days?

a) 40 days

b) 30 days

c) 35 days

d) 23.5 days

9) Rahul is twice as fast as Geetha and Geetha is twice as fast as Somu. If all of them work together can finish a work in 5 days, in how many days can Somu alone finish the work?

a) 40 days

b) 28 days

c) 35 days

d) 32 days

10) 5 men or 8 women can do a work in 18 days. How long will 10 men and 8 women take to finish the work?

a) 4 days

b) 8 days

c) 10 days

d) 6 days

Men Ã— Days/ Work = Men1 Ã— Days1/ Work1

3 Ã— 4 / 1 = Men1 Ã— 4/3

Men1 = 9

Men Ã— Days = Men1 Ã— Days1

Men Ã— 30 = (Men + 6) Ã— 15

Men Ã— 30 = 15 Men + 90

15 Men = 90

Men = 90/15 = 6

AÂ Â Â Â Â Â Â Â  BÂ Â Â Â Â Â Â Â Â  LCM

10Â Â Â Â Â Â Â  15Â Â Â Â Â Â Â  30 parts

3Â Â Â Â Â Â Â Â Â  2Â Â Â Â Â Â Â Â Â  5 parts in 1 day

12Â Â Â Â Â Â Â  8Â Â Â Â Â Â Â Â Â  20 parts in 4 day

That is 20 parts out of 30 parts work is already completed.

The remaining part of work left is 10/30 = 1/3

Total time taken = 24 Ã— 36 / (24 + 36)

= 24 Ã— 36 / 60

= 14 hours 24 mins

In 10 days John can finish 2/5th of work

In 1 day, he does = 2/(5×10) = 1/25

Ramâ€™s 1 day work = 50% (1/25)

= 1/50th work

Remaining work to be done = 1 â€“ 2/5 = 3/5

John and Ramâ€™s one day work = 1/25 + 1/50 = 3/50

3/5th work is done by them in (50/3) x (3/5) = 10 days

No of Days taken by Akash alone = 12 Ã— 8 / (12 â€“ 8)

= 12 Ã— 8 / 4

= 24 days.

Let the time taken by A to write book be 5 hours. Then, the time taken by B will be 10 hours.

From the above we can conclude that if the time taken by B is 2x hours, then time taken by A is x hours.

A Â Â Â Â Â Â Â  Â BÂ Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â  A+B

x daysÂ  2x days – 2Ã— (LCM)Â Â Â Â  24 days

2 partsÂ Â Â Â Â Â Â Â Â Â Â Â Â  1 partÂ Â  – 3 Ã— 24 = 72 units

The time taken by A alone is 72/2 = 36 days.

A+BÂ Â Â Â  B+CÂ Â Â Â  C+A

12Â Â Â Â Â Â Â  15Â Â Â Â Â Â Â  30Â Â Â Â Â Â Â  60 parts (LCM)

5Â Â Â Â Â Â Â Â Â  4Â Â Â Â Â Â Â Â Â  2Â Â Â Â Â Â Â Â Â  11 parts in 2 days

2A = A+B+C+A-(B+C) = 5+ 2-4 = 3

A = 3/2 = 1.5 units

No of days taken by A = 60/1.5 = 40 days

Rahul = 2 Geetha = 4 Somu

Rahul + geetha + somu = 4somu + 2somu + somu = 7 somu

Now 7 times of Somu can finish a work in 5 days then,

Somu alone can finish the work in 7Ã—5 = 35 days

5 menâ€™s work = 8 womenâ€™s work

1 manâ€™s work = 8/5 womenâ€™s work

10 menâ€™s work = (8/5) Ã— 10 = 16 womenâ€™s work

10 men + 8 women = 24 women

8 women can do a work in 18 days

So, 24 women can do the same work in 8 x 18 / 24 = 6 days.