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

Answer: Option 'A'

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

Answer: Option 'A'

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

Answer: Option 'D'

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

Answer: Option 'D'

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

Answer: Option 'D'

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

Answer: Option 'A'

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

Answer: Option 'B'

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

Answer: Option 'D'

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

Answer: Option 'C'

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

Answer: Option 'D'

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

Answer: Option 'B'

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

Answer: Option 'D'

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

Answer: Option 'D'

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

Answer: Option 'C'

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

Answer: Option 'A'

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

Answer: Option 'B'

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

Answer: Option 'B'

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

Answer: Option 'B'

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

Answer: Option 'D'

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

Answer: Option 'B'

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 number of days B will take to finish the work = 4 × 12/ 12 – 4 
= 48/8 = 6 days.

  • 21. 5 men can do a piece of work in 6 days while 10 women can do it in 5 days. In how many days can 5 women and 3 men do it?
   A.) 4
   B.) 5
   C.) 6
   D.) 8

Answer: Option 'B'

5men × 6 = 10 women × 5 
30 men = 50 women 
1 woman = 30/50 men = 3/5 men 
5 women = 3/5 × 5 men = 3 men 
5 women + 3 men = 3 + 3 = 6 men 
That is, 1 work done = 5 × 6 
5 × 6 = 6 × ?days 
? days = 5 × 6/6 = 5 days.

  • 22. A work could be completed in 100 days. However, due to the absence of 10 workers, it was completed in 110 days then, the original number of workers was 
   A.) 100
   B.) 110
   C.) 55
   D.) 50

Answer: Option 'B'

Let ‘x’ be the original number of workers 
Then, x × 100 = ( x – 10) 110 
100 x = 110x – 1100 
1100 = 10 x 
x = 110.

  • 23. A particular job can be completed by a team of 10 men in 12 days. The same job can be completed by a team of 10 women in 6 days. How many days are needed to completed the job if the two teams work together? 
   A.) 4
   B.) 6
   C.) 18
   D.) 9

Answer: Option 'A'

Consider men’s work days as one group and women’s working days as other group Then, the required No. of days = 12 × 6/18 = 4 days.

  • 24. A can do a piece of work in 12 days, while B can do it in 8 days with the help of C, they finish the work in 4 days. Then C alone can do the work in 
   A.) 24 days
   B.) 20 days
   C.) 16 days
   D.) 4 days

Answer: Option 'A'

A and B together can do the work in 12 × 8/20 = 96/20 days 
A +B and C together do the work in 4 days. 
Then C alone can do the work in 96/20 × 4/96/20 – 4 days 
= 96/5/16/20 = 96/5 × 20/16 = 24 days.

  • 25. A job can be completed by 12 men in 12 days. How many extra days will be needed to complete the job if 6 men leave after working for 6 days? 
   A.) 12
   B.) 10
   C.) 8
   D.) 6

Answer: Option 'D'

Half the work is done by 12 men in 6 days. 
Remaining half should be done by 6 men in ? days 
Then, 12 × 6 × ½ = 6 × ?days × ½ 
36 = 3 × ?days
? days = 36/3 =12 days 
Extra days required = 12 -6 = 6 days.

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