A and B can do a work in 10 days and 15 days respectively. A starts the work and B joins him after 5 days. In how many days can they complete the remaining work?
Options:
(A) 6 days
(B) 2 days
(C) 8 days
(D) 4 days
(E) 3 days Now, let's think a bit. Some random thoughts:
Work done by A in 5 days = 5/10 = 1/2
Remaining work = 1/2
Work done by both A and B in one day = 1/10 + 1/15 = 5/30 = 1/6
Remaining work = 1/2 * 6/1 = 3 days.
The final answer: (E).