Two pipes fill a tank in 20 and 30 minutes; a drain empties it in 15 minutes. If the tank is half full, and the pipes and the drain are opened…
Two pipes fill a tank in 20 and 30 minutes; a drain empties it in 15 minutes. If the tank is half full, and the pipes and the drain are opened together, how long will it take to fill the tank?
From the BB Assistant Director (General) July 2026 – Preliminary exam, question 40 of 100.