X can finish a work in 36 days. Y can finish the same work in 24 days. Y worked for 12 days and left the job. how many days does X alone need to finish the remaining work?
Options:
(A) 12
(B) 13
(C) 16
(D) 17
(E) 18 Think first, then make a decision. Some random thoughts:
Work done by X in 1 day = 1/36
Work done by Y in 1 day = 1/24
Work done by Y in 12 days = 12/24 = 1/2
Remaining work = 1 1/2 = 1/2
Number of days in which X can finish the remaining work = (1/2) / (1/36) = 18 So the answer is (E).