Q: A and B together can complete a work in 12 days. A alone can complete it in 20 days. If B does the work only for half a day daily, then in how many days A and B together will complete the work?\nOptions:\n(A) 11 days\n(B) 77 days\n(C) 15 days\n(D) 18 days\n(E) 19 days Let's give some random thoughts before answering.
User
B's 1 day work = (1/12 - 1/20) = 1/30\nNow, (A + B)'s 1 day work = (1/20 + 1/60) = 1/15\nSo, A and B together will complete the work in 15 days.
Therefore, the answer is (C).
Assistant