The hot water needs of a household are met by a 60 L electric water heater whose heaters are rated at 1.6 kW. The hot water tank is initially full with hot water at 80 C. Somebody takes a shower by mixing a constant flow of hot water from the tank with cold water at 20 C at a rate of 0.06 kg/s. After a shower period of 8 min, the water temperature in the tank is measured to drop to 60 C. The heater remained on during the shower and hot water withdrawn from the tank is replaced by cold water at the same flow rate. Determine the mass flow rate of hot water withdrawn from the tank during the shower and the average temperature of mixed water used for the shower.