Thermodynamics Part 1

Two cornot engines A and B are operated in series. Engine A receives heat from a reservoir at 600 K and rejects heat to a reservoir at temperature T. Engine B receives heat rejected by engine A and in turn rejects it to a reservoir at 100 K . If the efficiencies of the two engines A and B are represented by ηA and ηB, respectively, then what is the value of ‌

ηB

ηA

?