A, B, and C can do a piece of work in 30, 20, and 10 days respectively. A is assisted by B on one day and by C on the next day, alternately. How many days will it take to finish the work?
Q1. A, B, and C can do a piece of work in 30, 20, and 10 days respectively. A is assisted by B on one day and by C on the next day, alternately. How many days will it take to finish the work?
Answer: 9 days
Explanation: Work done on the first day = 1/30 + 1/20 = 5/60 = 1/12. Work done on the second day = 1/30 + 1/10 = 4/30 = 2/15. Average work per day = (1/12 + 2/15)/2.