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?
Options:
(A) 30days
(B) 45 days
(C) 80 days
(D) 72 1/2 days
(E) 72 days Random thoughts:
1/45+ 1/30 = 5/90 = 1/18
18/1 = 18*4 = 72 days The final answer: (E).