RRB NTPC - Time and Work :(96) MCQs with Answers

1.

A completes a work in 12 days and B complete the same work in 24 days. If both of them work together, then the number of days required to complete the work will be

A.) 8 days
B.) 6 days
C.) 7 days
D.) 5 days

If A can complete a work in x days and B can complete the same work in y days, then, both
of them together can complete the work in x y/ x+ y days
Therefore, here, the required number of days = 12 × 24/ 36 = 8 days.

2.

If 4 men can colour 48 m long cloth in 2 days, then 6 men can colour 36 m long cloth in

A.) 1 days
B.) 1 ½ days
C.) ¾ day
D.) ½ day

The length of cloth painted by one man in one day = 48 / 4 × 2 = 6 m
No. of days required to paint 36 m cloth by 6 men = 36/ 6 × 6 = 1 day.

3.

If 3 persons can do 3 times of a particular work in 3 days, then, 7 persons can do 7 times of that work in

A.) 7 days
B.) 6 days
C.) 4 days
D.) 3 days

That is, 1 person can do one time of the work in 3 days.
Therefore, 7 persons can do 7 times work in the same 3 days itself.

4.

Mangala completes a piece of work in 10 days, Raju completes the same work in 40 days. If both of them work together, then the number of days required to complete the work is

A.) 15 days
B.) 10 days
C.) 9 days
D.) 8 days

If A can complete a work in x days and B can complete the same work in y days, then, both
of them together can complete the work in x y/ x+ y days.
That is, the required No. of days = 10 × 40/50 = 8 days.

5.

12 men work 8 hours per day to complete the work in 10 days. To complete the same work in 8 days, working 15 hours a day, the number of men required

A.) 4 days
B.) 5 days
C.) 6 days
D.) 8 days

That is, 1 work done = 12 × 8 × 10
Then, 12 8 × 10 = ? × 15 × 8
? (i.e. No. of men required) = 12 × 8 × 10/15× 10 = 8 days.

6.

If 5 people undertook a piece of construction work and finished half the job in 15 days. If two people drop out, then the job will be completed in

A.) 25 days
B.) 20 days
C.) 15 days
D.) 10 days

That is, half the work done = 5 × 15 × ½
Then, 5 × 15 × ½ = 3 × ? ×1/2
i.e. 5 × 15 = 3 × ?
therefore, ? (No. days required) = 5 × 15/3 = 25 days.

7.

30 labourers working 7 hours a day can finish a piece of work in 18 days. If the labourers work 6 hours a day, then the number of labourers required to finish the same piece of work in 30 days will be

A.) 15 days
B.) 21 days
C.) 25 day
D.) 22 day

That is, 1 work done = 30 × 7 ×18 = ? × 6 × 30
? (No. of labourers) = 30 × 7 × 18/6 × 30 = 21

8.

If 5 girls can embroider a dress in 9 days, then the number of days taken by 3 girls will be

A.) 20 days
B.) 10 days
C.) 14 days
D.) 15 days

That is, 5 × 9 = 3 × ?
? = 5 × 9/3 = 15 days

9.

A and B together can plough a field in 10 hours but by himself A requires 15 hours. How long would B take to plough the same field?

A.) 10 hours
B.) 20 hours
C.) 30 hours
D.) 40 hours

If A and B together can do a piece of work in x days and A alone can do the same work in y days, then B alone can do the same work in x y/ y – x days.
Therefore, the No. of hours required by B = 10 × 15/ 15 – 10 = 150/5 = 30 hours.

10.

16 men or 20 women can finish a work in 25 days. How many days 28 men and 15 women will take to finish this job?

A.) 19 13/43 days
B.) 11 27/43 days
C.) 8 days
D.) 10 days

16 men = 20 women
Therefore, 1 women = 16/20 men = 4/5 men
15 women = 4/5 × 15 men = 12 men
i.e. 28 men + 15 women = 28 men + 12 men = 40men
1 work done by men = 16 × 25
16 × 25 = 40 × ?
? ( no. of days) = 16 × 25/40 = 10 days.

11.

A can do a piece of work in 5 days and B can do the same work in 10 days. How many days will both take to complete the work?

A.) 5 days
B.) 3 1/3 days
C.) 3 days
D.) 6 days

If A can complete a work in x days and B can complete the same work in y days, then, both
of them together can complete the work in x y/ x+ y days.
That is, the required No. of days = 5 × 10/15 = 3 1/3 days.

12.

If 12 men can do a piece of work in 24 days, then in how many days can 18 men do the same work?

A.) 36
B.) 20
C.) 18
D.) 16

1 work done = 12 × 24
Then, 12 × 24 = 18 × ? days
? days = 12 × 24/18 = 16.

13.

A group of workers accepted to do a piece of work in 25 days. If 6 of them did not turn for the work and the remaining workers did the work in 40 days, then the original number of workers was

A.) 22
B.) 21
C.) 20
D.) 16

Let the original number of workers be ‘x’
Then, x × 25 = (x – 6) × 40
25x = 40x -240
240 = 40x -25x = 15x
x = 240/15 = 16.

14.

If 8 men or 12 women can do a piece of work in 10 days, then the number of days required by 4 men and 4 women to finish the work is

A.) 8
B.) 10
C.) 12
D.) 14

8 men = 12 women
1 woman = 8/12 men = 2/3 men
4 women = 2/3 × 4 men = 8/3 men
4 men + 4 women = 4 + 8/3 men = 20/3 men
1 work done = 8 × 10
8 × 10 = 20/3 × ?days
? days = 8 × 10 × 3/20 = 12 days.

15.

If 8 men can dig a well in 18 days, then the number of days, 12 men will take to dig the same well will be

A.) 12 days
B.) 10 days
C.) 8 days
D.) 16 days

Work done = 8 × 18
Then, 8 × 18 = 12 × ? days
? days = 8 × 18/12 = 12 days

16.

39 men can repair a road in 12 days working 5 hours a day. In how many days will 30 men working 6 hours peer day complete the work?

A.) 10
B.) 13
C.) 14
D.) 15

1 work done = 39 × 12 × 5
39 × 12 × 5 = 30 × 6 × ? days
? days = 39 × 12 × 5/ 30 × 6 = 13 days.

17.

A certain number of men can do a work in 40days. If there were 8 men more, it could be finished in 10 days less. How many men were there initially?

A.) 30
B.) 24
C.) 16
D.) 20

Let ‘x’ be the initial number of men
Then, 1 work done = x × 40
Then, x × 40 = (x + 8 ) (40 – 10)
40x = 30x + 240
10x = 240
Therefore, x = 240/10 = 24 men.

18.

If 4 men or 6 boys can finish a work in 20 days. How long will 6 men and 11 boys take to finish the same work?

A.) 10 days
B.) 6 days
C.) 4 days
D.) 3 days

4 men = 6 boys
Then, 1 boy = 4/6 men = 2/3 men
11 boys = 2/3 × 11 men = 22/3 men
Then, 6 men + 11 boys = 6 + 22/3 men = 40/3 men
1 work done = 4 men × 20days
That is, 4 × 20 = 40/3 × ? days
? days = 4 × 20 × 3/40 = 6 days

19.

A works twice as fast as B. if B can complete a work in 12 days independently. The number of days in which A and B can together finish the work?

A.) 18 days
B.) 8 days
C.) 6 days
D.) 4 days

If B takes 12 days to finish the work, then A takes 6 days to finish the same work.
If A can complete a work in x days and B can complete the same work in y days, then, both of them together can complete the work in x y/ x+ y days.
Therefore, the Number of days taken by A and B together to finish the same work = 6 × 12/18
= 4 days.

20.

A and B can do a piece of work in 4 days. If A can do it alone in 12 days, B will finish the work in

A.) 4 days
B.) 6 days
C.) 8 days
D.) 10 days