Use some thinking to answer the following question. A can do a job in 45 days and B can do it in 30 days. A and B working together will finish four times the amount of work in ------- days?\nOptions:\n(A) 30days\n(B) 45 days\n(C) 80 days\n(D) 72 1/2 days\n(E) 72 days
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1/45+ 1/30 = 5/90 = 1/18\n18/1 = 18*4 = 72 days So the final answer is (E).
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