Ravi can do a piece of work in 30 days while Prakash can do it in 40 days. In how many days will they finish it together?
Options:
(A) 19 1/7 days
(B) 16 1/7 days
(C) 14 1/7 days
(D) 17 1/7 days
(E) 13 1/7 days Hmmm, my stream of consciousness:
1/30 + 1/40 = 7/120
120/7 = 17 1/7 days So, the answer is (D).