Cold water has a temperature of 10C, and hot water – 70C. How much hot and cold water should

Cold water has a temperature of 10C, and hot water – 70C. How much hot and cold water should be mixed to get 200 liters of water with a temperature of 30C.

Since the steady-state temperature is 30 ºС, cold water will heat up by 20 ºС (30 ºС – 10 ºС = 20 ºС), and hot water will cool down by 40 ºС (70 ºС – 30 ºС = 40 ºС).

Consequently, 1 kg of hot water can heat up to 30 ºС 2 kg of cold and the ratio of the mass of cold and hot water 2: 1 (2/3 of cold water and 1/3 of hot).

To obtain 200 liters of water with a temperature of 30 ºС, you must:

mх = 200 * 2/3 = 133.3 kg.

mg = 200/3 = 66.7 kg.

Answer: You need 133.3 liters of cold water and 66.7 liters of hot water.