1.

Ram and Shyam together can finish a job in 8 days. Ram can do the same job on his own in 12 days. How long will Shyam take to do the job by himself?

 A. 16 days B. 20 days C. 24 days D. 30 days
Explanation: 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 days Shyam take to finish the job alone = 8 -12/12 * 8 = 8 -12/4 = 24 days.

2.

A does 4/5th of a work in 20 days. He then calls in B and they together finish the remaining work in 3 days. How long B alone would take to do the whole work?

 A. 23 days B. 37 days C. 37½ days D. 40 days
Explanation: A can finish the whole work in 20 - 5/4 days = 25 days A and B together finish the whole work in 5 - 3 days = 15 days Therefore, B can finish the whole work in 25 B/ 25 + B = 15 25 B = 15 (25+B)= 375 + 15B 10B = 375 and B = 375/10 = 37½ days

3.

A and B together can complete a work in 12 days. A alone can complete it in 20 days. If B does the work only for half a day daily, then in how many days A and B together will complete the work?

 A. 11 days B. 13 days C. 15 days D. 17 days
Explanation: B's 1 day's work = (1/12 - 1/20) = 2/60 = 1/30 Now, (A + B)'s 1 day's work = (1/20+1/60) = 4/60 = 1/15. [B works for half day only] So, A and B together will complete the work in 15 days

4.

8 men can do a piece of work in 12 days. 4 women can do it in 48 days and 10 children can do it in 24 days. In how many days can 10 men, 4 women and 10 children together complete the piece of work?

 A. 5 days B. 15 days C. 28 days D. 6 days
Explanation:

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. 6 days B. 6.4 days C. 6.8 days D. 7 days