A hot-water stream at 70C enters an adiabatic mixing chamber with a mass flow rate of 3.6

Question:

A hot-water stream at 70°C enters an adiabatic mixing chamber with a mass flow rate of 3.6 kg/s, where it is mixed with a stream of cold water at 20°C. If the mixture leaves the chamber at 42°C, determine
(a) The mass flow rate of the cold water and
(b) The rate of entropy generation during this adiabatic mixing process. Assume all the streams are at a pressure of 200 kPa.