The kiloton, which is used to measure the energy released in an atomic explosion, is equal to 4.2 multiplied by 1012 J (approximately the energy released in the explosion of 1000 tons of TNT). Recalling that 1 kilocalorie of energy raises the temperature of 1 kg of water by 1°C and that 4184 joules is equal to 1 kilocalorie, calculate how many kilograms of water can be heated through 50°C by a 15 kiloton atomic bomb.