A and B can complete a piece of work in 20 days. B and C can complete it in 30 days. A is twice as good as C in completing the work. Find in how many days will B alone complete it.

Show answer & explanation

Answer: (A) 60 days

Explanation

A + B = 1/20 and B + C = 1/30, so A − C = 1/60. With A = 2C, C = 1/60, and B = 1/30 − 1/60 = 1/60. B alone takes 60 days.