Answer:
55%
Step-by-step explanation:
hot reservoir = 1100 K
cold reservoir = 500 K
This is a Carnot system
For a Carnot system, maximum efficicency of the system is given as
Eff = 1 -

where Tc = temperature of cold reservoir = 500K
Th = temperature of hot reservoir = 1100 K
Eff = 1 -

Eff = 1 - 0.45 = 0.55 or 55%