One pipe fills a water tank in 6 hours and a second pipe fills it in 3 hours. How long will both pipes together take to fill the tank?
Q1. One pipe fills a water tank in 6 hours and a second pipe fills it in 3 hours. How long will both pipes together take to fill the tank?
Answer: 2 hours
Explanation: Combined filling rate is 1/6 plus 1/3, which equals 1/2 of the tank per hour. The tank fills in 2 hours.