A and B together can complete a piece of work in 10 days. B alone can complete it in 15 days. In how many days can A alone complete the work?
Show answer & explanation
Correct answer: C
Explanation
(A + B)'s 1-day work = 1/10
B's 1-day work = 1/15
A's 1-day work = 1/10 − 1/15
= (3 − 2)/30
= 1/30
Therefore, A alone will complete the work in 30 days.