A, B, and C can do a work in 10, 15, and 20 days respectively. How long will they take to complete the work together?
Q1. A, B, and C can do a work in 10, 15, and 20 days respectively. How long will they take to complete the work together?
Answer: 4.7 days
Explanation: Their combined rate of work = 1/10 + 1/15 + 1/20 = (6 + 4 + 3)/60 = 13/60. So, time taken = 60/13 = 4.62 days.