Consider two Carnot heat engines operating in series. The first engine receives heat from the reservoir at 1800 K, and rejects the waste heat to another reservoir at temperature T.
The second engine receives the energy rejected by the first one, converts some of it into work, and rejects the rest to a reservoir at 300 K. If the thermal efficiencies of both engines are the same, determine temperature T.
Efficiency of a Carnot Heat Engine = N = 1 - (Tr/Ta)
where Tr = Rejection ...
This solution provides calculations for determining temperature of an engine.