A Real (Non-Carnot) Heat Engine, Operating Between Heat Reservoirs at Temperatures

Short Answer

A real (non-Carnot) heat engine, operating between heat reservoirs at temperatures of 450 $\mathrm { K }$ and $270 \mathrm {~K}$ , performs $3.3 \mathrm {~kJ}$ of net work, and rejects $8.2 \mathrm {~kJ}$ of heat in a single cycle.
(a) What is the thermal efficiency of this heat engine?
(b) What is the maximum efficiency it could possibly have?