Q. Two pipes fill a tank in 20 hours and 30 hours respectively. If both are opened together, after how many hours will half the tank be filled?
✅ Correct Answer: (B)
7.5 hours
Explanation: Net rate = 1/20 + 1/30 = 1/12 → half tank in 6 hours.
Explanation by: Kanak Sharma
Net rate = 1/20 + 1/30 = 1/12 → half tank in 6 hours.