Answer:
55.56%
Step-by-step explanation:
Given data
Temprature of hot reservior =2000°c=2273k
Temprature of Cold reservior=25°c=298k
Power produced by engine=50MW
Heat rejected =40MW
we know that Effeciency(η) of heat engine=

Also we know that
heat supplied
Q_s=50+40=90MW
η=

η=

η=55.55%