Give a quick stream of consciousness before answering the following question. A can do a job in 12 days and B can do it in 15 days. A and B working together will finish twice the amount of work in days?
Options:
(A) 22 1/6
(B) 22 1/2
(C) 22 1/0
(D) 22 1/9
(E) 13 1/3
1/12 + 1/15 = 9/60 = 3/20
20/3 = 20/3 *2 = 13 1/3 days
The answer: (E).