Hot water is provided to a house by an electric water heater which uses a 60L tank. The electric heater is rated for a 1.6kW. The hot water tank is completely full with water at 80°C when someone starts a shower. The shower faucet mixes cold water at 20°C and a flow rate of 0.06kg/s with hot water at an unknown flow rate from the water heater. After an 8min shower period, the water in the hot water heater has dropped to a temperature of 60°C. The heater ran continuously during the shower period and drew in cold water at 20°C at the same rate as hot water left it. What was the mass of hot water withdrawn from the tank?