4. (*) An empty adiabatic room, initially at 20C, has a volume of 100 m. A tank that contains 85C liquid water with a mass of 30 kg is placed into the room. The room air and the water tank reached thermal equilibrium after a while due to the heat transfer between the tank and the room. Assume constant specific heats to calculate, a. the final temperature at the thermal equilibrium b. the amount of heat transfer between the water and the room air the entropy generation. .