A, B, and C can complete a work in 10, 15, and 20 days, respectively. They start the work together, but A leaves after 2 days, and B leaves 1 day before the completion. How many days will it take to complete the work?
Q1. A, B, and C can complete a work in 10, 15, and 20 days, respectively. They start the work together, but A leaves after 2 days, and B leaves 1 day before the completion. How many days will it take to complete the work?
Answer: 7 days
Explanation: A's 1 day work = 1 / 10, B's = 1 / 15, C's = 1 / 20. Work done in first 2 days = 2 * (1 / 10 + 1 / 15 + 1 / 20) = 2 * (13 / 60) = 13 / 30.