A 50 liters of rigid tank contains 1 kg of saturated steam of vapor & liquid at 80 C. If 2000 kJ of heat is added to the system by direct heat transfer to the surroundings at a temperature of 30 C, calculate the entropy change of the system.

Hint 1: Final temperature must be between 100 C and 300 C.

Hint 2: Use steam tables.