In an undisclosed process which is said to be completely reversible, the state of an ideal gas (with Cp=7/2R) has been changed from 500K and 5 bar to 300K and 1 bar. In the process, a certain amount of heat has been transferred from the system to an external hint sink at 300K. If the process is indeed completely reversible, how much heat was rejected to the heat sink. [Hint: Consider first the entropy change for the system which is the ideal gas]