A faucet can fill a sink in 3 minutes. It takes 2 times as long for the drain to empty the sink. How long will it take to fill the sink if the drain is open and the faucet is on?
the faucet and drain are open.
Let the volume of sink is
The sink is drained out to empty in
When both the faucet and drain is open the sink fills
completely required time is
the faucet and drain is open [Ans]