In order to cool 1 ton of water at 20°C in an insulated tank, a person pours 140 kg of ice at –5°C into the water. The specific heat of water at room temperature is c = 4.18 kJ/kg· °C, and the specific heat of ice at about 0°C is c = 2.11 kJ/kg°C. The melting temperature and the heat of fusion of ice at 1 atm are 0°C and 333.7 kJ/kg.