A puzzle from Chris Maslanka’s The Pyrgic Puzzler, 1987:
A bathtub will fill in 3 minutes if the plug is in and the cold tap only is turned on full. It will fill in 4 minutes if the plug is in and the hot tap only is turned on full. With the plug out and both taps off, a full tub will drain in 2 minutes. How long will it take to fill the empty tub if the plug is out and both taps are turned on full?
