1. The problem statement, all variables and given/known data A heat engine operates between a high-temperature reservoir at 690 K and a low-temperature reservoir at 320 K. In one cycle, the engine absorbs 6700 J of heat from the high-temperature reservoir and does 2200 J of work. What is the magnitude of the net change in entropy as a result of this cycle? 2. Relevant equations delta S =Q/T 3. The attempt at a solution Qh= 6700 Th=690 Qc=Qh-W=6700-2200=4500 Tc=320 delta S= (-6700/690)+(4500/320)= 4.4 J/K But i got the answer wrong, Where did i make a mistake, did i not round off correctly, or is the formula i used incorrect.