Two flows of air are both at 200 kPa; one has 2 kg/s at 400 K, and the other has 1 kg/s at 290 K. The two flows are mixed together in an insulated box to produce a single exit flow at 200 kPa. The air can be approximated as an ideal gas. The specific heat (Cv) and gas constant (R) of air are 716 J/kg-K and 287 J/kg-K, respectively. Find the exit temperature and the total rate of entropy generation. What is the possible reason for the positive entropy generation in this case