A can do a work in 15 days, B in 30 days. They start together but A leaves after 5 days. In how many more days will B complete the remaining work?
Show answer & explanation
Correct answer: A
Explanation
A's work rate = 1/15
B's work rate = 1/30
(A + B)'s work rate = 1/15 + 1/30 = 1/10
Work done in 5 days = 5 × 1/10 = 1/2
Remaining work = 1 − 1/2 = 1/2
B's work rate = 1/30
Time = (1/2) ÷ (1/30) = 15 days