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? Choose the correct option: 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
1/30 + 1/40 = 7/120   120/7 = 17 1/7 days   ANSWER:17 1/7 days
<result>D</result>
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?