A men can do a piece of work in 5 days. With the help of his friend, he can do the same work in 3 days. In how many days can his friend complete the work?
Correct Answer: 71/2
Explanation:
(Man and his friend)'s 1 day's work = 1/3
Men's 1 day's work = 1/5
His friend's 1 day's work is = 1/3 - 1/5 = 2/15
Hence, his friend can complete the work in 15/2 = 71/2
