A tank is filled by three pipes, A, B, and C, in 10, 15, and 20 hours, respectively. How long will it take to fill the tank if all pipes are opened together?
Q1. A tank is filled by three pipes, A, B, and C, in 10, 15, and 20 hours, respectively. How long will it take to fill the tank if all pipes are opened together?
Answer: 4.7 hours
Explanation: The combined rate = 1/10 + 1/15 + 1/20 = (6 + 4 + 3)/60 = 13/60. So, the time taken = 60/13 = 4.615 hours, approximately 4.7 hours when rounding to one decimal place.