Question

In each cycle of a Carnot engine, 97 J of heat is
absorbed from the high-temperature reservoir
and 50 J is exhausted to the low-temperature
reservoir.
What is the efficiency of the engine?

Answer 1

This maximum efficiency η is defined to be:
η= W/Q_H = (T₁-T₂)/T₁ =1-T₂/T₁ =1-Q₂/Q₁

Where W is the work done by the system (energy exiting the system as work), Q_H is the heat put into the system (heat energy entering the system), T₂ is the absolute temperature of the cold reservoir, and T₁ is the absolute temperature of the hot reservoir.
So
η=1-Q₂/Q₁ =1-50/97=1-0.515=0.485.