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Time and Work Questions Answers

Q1 :

If 5 men and 8 boys can complete a work in 15 days, and 5 men and 3 boys in 20 days, then 12 boys can complete the same work in

A
  

15 days

B
  

20 days

C
  

25 days

D
  

36 days

View Answer
Correct Answer: C

25 days

No Description Available
Q2 :

15 men can do a piece of work in 20 days. In how many days 25 men finish the same work?

A
  

2

B
  

20

C
  

12

D
  

15

View Answer
Correct Answer: C

12

Description:

=15×2025=12=frac{15 times 20}{25} = 12

Q3 :

If 3 men or 6 boys can do a piece of work in 20 days, how many days will 6 men and 8 boys take to do the same work?

A
  

6

B
  

8

C
  

10

D
  

12

View Answer
Correct Answer: A

6

Description:

3 men = 6 boys or 1 man = 2 boys

6 men + 8 boys = (2×6+8)(2 times 6 + 8) boys or 20 boys

if 6 boys can do a job in 20 days

therefore20 boys can do a job in 6×2020=6 daysfrac{6 times20}{20} = 6 text{ days}
 

Q4 :

A can copy 75 pages in 25 hours, A and B together can copy 135 in 27 hours. In what time can B copy 42 pages?

A
  

17 hours

B
  

27 hours

C
  

21 hours

D
  

31 hours

View Answer
Correct Answer: C

21 hours

Description:

A can copy 3 pages in one hour whereas both can copy 5 pages (135 + 27)  in one hour, meaning that, B can copy only 2 pages in one hour. Thus B can copy 42 pages in 21

Q5 :

A can do a piece of work in 6236 frac{2}{3} days and B is 5 days. They work together for 2 days and then A leaves B to finish the work alone. How long will B take to finish it?

A
  

34frac{3}{4} days

B
  

7 days

C
  

1121frac{1}{2} days

D
  

3 days

View Answer
Correct Answer: C

1121frac{1}{2} days

Description:

2 days work done by A and B

=2×[1623+15]=2×[920+15]=710= 2 times Bigg[dfrac{1}{6 frac{2}{3}}+frac{1}{5}Bigg] = 2 times Big[frac{9}{20} + frac{1}{5} Big] = frac{7}{10}

Remaining work =1710=310= 1 - frac{7}{10} = frac{3}{10}

This 310frac{3}{10} of the work can be finished in 310×5frac{3}{10} times 5 , i.e.,  112 days1 frac{1}{2} text{ days}

Q6 :

A can do a piece of work in 20 days, B in 15 days and C in 12 days. How soon can the work be done if A is assisted by B on one day and by C on the next alternately?

A
  

14 days

B
  

10 days

C
  

8 days

D
  

6 days

View Answer
Correct Answer: C

8 days

Description:

(A + B)'s 1 days's work =(120+115)= Big(frac{1}{20} + frac{1}{15} Big) of the work i.e., 760frac{7}{60}

(A + C)'s 1 days's work =(120+112)= Big(frac{1}{20} + frac{1}{12} Big) of the work i.e., 860frac{8}{60} of the work.

2 days work done =760+860=14= frac{7}{60} + frac{8}{60} = frac{1}{4}

Since 14frac{1}{4} of work done in 2 days, so whole of the work done in 8 days

Q7 :

A can do a piece of work in 14 days and B in 21 days. They begin together but 3 days before the completion of the work. A leaves off. In how many days is the work complete?

A
  

10 days

B
  

101510 frac{1}{5} days

C
  

15 days

D
  

7 days

View Answer
Correct Answer: B

101510 frac{1}{5} days

Description:

(A + B)'s 1 day's work =114+121=3+242=542= frac{1}{14} + frac{1}{21} = frac{3 + 2}{42} = frac{5}{42}

At the end, B works for 3 days so work done by B in 3 days =3×121=17= 3 times frac{1}{21} = frac{1}{7}.

Remaining work =117=67= 1 - frac{1}{7} = frac{6}{7} which is to be done by A and B.

542frac{5}{42} of the work (A + B) can do in 1 day

67therefore frac{6}{7} of work (A + B) can do is 1542×67=715 daysdfrac{1}{frac{5}{42}} times frac{6}{7} = 7 frac{1}{5} text{ days}

therefore Time to complete the work

=3+715=1015= 3 + 7frac{1}{5} = 10frac{1}{5} days

Q8 :

If the wages of 45 woman amount to Rs. 15525 in 48 days, how many men must work 16 days to receive Rs. 5750. The daily wages of a man being double that of a woman?

A
  

30 men

B
  

15 men

C
  

25 men

D
  

20 men

View Answer
Correct Answer: C

25 men

Description:

45 women can earn Rs. (15525÷3)(15525 div 3 ) in 16 days, i.e., Rs. 5175

or 221222frac{1}{2} men can earn in 16 days Rs. 5175.

Now Rs. 5175 is the earning for 221222 frac{1}{2} men

therefore Rs. 5750 is the earning for

=22125175×5750=25= dfrac{22frac{1}{2}}{5175} times 5750 = 25

Q9 :

If 5 men and 2 boys working together can do four times as much work per hour as a man and a boy together. Compare the work of a man with that of a boy?

A
  

1 : 2

B
  

2 : 1

C
  

1 : 3

D
  

1 : 4

View Answer
Correct Answer: B

2 : 1

Description:

5 men +2 boys =4×(1 man+1 boy)5 text{ men } + 2 text{ boys } = 4 times (1 text{ man} + 1 text{ boy} )

1 man =2 boystherefore 1 text{ man } = 2 text{ boys}

Required ratio = 2 : 1

Q10 :

A can do a piece of work in 40 days. He worked at it for 5 days, then B finished it in 21 days. The number of days that A and B will take together to finish the same work is

A
  

25 days

B
  

15 days

C
  

12 days

D
  

10 days

View Answer
Correct Answer: B

15 days

Description:

Work done by A in 5 days =140×5=18= frac{1}{40} times 5 = frac{1}{8}

Remaining 7/8 th of the work is done by B in 21 days.

B's 1 day's work =78×121=124= frac{7}{8} times frac{1}{21} = frac{1}{24}

A + B's 1  days's work =140+124=3+5120=115= frac{1}{40} + frac{1}{24} = frac{3 + 5}{120} = frac{1}{15}

therefore Both can do it in 15 days.

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