The ones who are crazy enough to think they can change the world are the ones who do.

- Steve Jobs

Problems on Time and Work

Time and Work - Aptitude

1.A does a work in 10 days and B does the same work in 15 days. In how many days they together will do the same work?

x

Option: D

Explanation

A's 1 day's work = 1/10

B's 1 day's work = 1/15

(A + B)'s 1 day's work = (1/10) + (1/15) = 1/6

i.e) both together will finish the work in 6 days

✉ Answer

2.A can finish a work in 18 days and B can do the same work in half the time take by A. Then, working together, what part of the same work they can finish in a day?

x

Option: A

Explanation

A's 1 day's work = 1/18

B's 1 day's work = 1/9

(A + B)'s 1 day's work = (1/18) + (1/9) = 1/6

✉ Answer

3.The tyre has 2 punctures. The first puncture alone would have made the tyre flat in 9 minutes and the second alone would have done it in 6 minutes.If air leaks out at a constant rate, how long does it take both the punctures together to make it flat?

x

Option: D

Explanation

1 minute's work of both the punctures = (1/9) + (1/6) = 5/18

so, both the punctures will make the tyre flat in 18/5 minutes

✉ Answer

4.A, B, and C can complete a piece of work in 24, 6 and 12 days respectively. working together, they will complete the same work in:

x

Option: A

Explanation

(A + B + C)'s 1 day's work = (1/24) + (1/6) + (1/12) = 7/24

so, A, B and C together will complete the job in 24/7 days

✉ Answer

5.A man can do a job in 15 days. His father takes 20 days and his son finishes it in 25 days. How long will they take to complete the job if they all work together?

A. exactly 6 days✘

B. Approximately 6.4 days✔

C. less than 6 days✘

D. more than 7 days✘