Use some thinking to answer the following question. A and B can do a work in 10 days and 15 days respectively. A starts the work and B joins him after 2 days. In how many days can they complete the remaining work?
Options:
(A) 6 days
(B) 2 days
(C) 4 4/5 days
(D) 3 days
(E) 9 days
user
Work done by A in 2 days = 2/10 = 1/5
Remaining work = 4/5
Work done by both A and B in one day = 1/10 + 1/15 = 5/30 = 1/6
Remaining work = 4/5 * 6/1 = 24/5 = 4 4/5 days. So the final answer is (C).
assistant