For a conventional, gas-fired hot water heater, with a constant water flow rate of 9.6 L/min entering at room temperature (21 deg. C), we want to determine how long the exit flow rate will remain above body temperature (37 deg. C) if the gas is suddenly stopped. The water heater contains 140 kg of water at an initial temperature of 62.3 deg. C, where you can assume a constant heat capacity of water (4.186 J/g/C). Enter your answer with units of time in minutes (for example: "7.9 min").