36.

A can do a piece of work in 15 days and B alone can do it in 10 days. B works at it for 5 days and then leaves. A alone can finish the remaining work in

 A. 5 days B. 6 days C. 7.5 days D. 8.5 days
Explanation: B's 5 days work = 1 10 ∗5= 1 2 Remaining work =1− 1 2 = 1 2 A can finish work =15∗ 1 2 =7.5days

37.

A can do a piece of work in 4 hours . A and C together can do it in just 2 hours, while B and C together need 3 hours to finish the same work. In how many hours B can complete the work ?

 A. 10 hours B. 12 hours C. 16 hours D. 18 hours
Explanation: Work done by A in 1 hour = 1/4 Work done by B and C in 1 hour = 1/3 Work done by A and C in 1 hour = 1/2 Work done by A,B and C in 1 hour = (1/4)+(1/3) = 7/12 Work done by B in 1 hour = (7/12)�(1/2) = 1/12 => B alone can complete the work in 12 hour

38.

A completes 80% of a work in 20 days. Then B also joins and A and B together finish the remaining work in 3 days. How long does it need for B if he alone completes the work?

 A. 35 1 2 B. 36 1 2 C. 37 1 2 D. 38 1 2
Explanation: Work done by A in 20 days = 80/100 = 8/10 = 4/5 Work done by A in 1 day = (4/5) / 20 = 4/100 = 1/25 --- (1) Work done by A and B in 3 days = 20/100 = 1/5 (Because remaining 20% is done in 3 days by A and B) Work done by A and B in 1 day = 1/15 ---(2) Work done by B in 1 day = 1/15 � 1/25 = 2/75 => B can complete the work in 75/2 days = 37 (1/2) days

39.

A alone can do a piece of work in 6 days and B alone in 8 days. A and B undertook to do it for Rs. 3200. With the help of C, they completed the work in 3 days. How much is to be paid to C

 A. 300 B. 400 C. 500 D. 600