Hey Ankit! 

The temperature of source of Carnot heat engine is 127c. It takes 500 calories of heat from the source and rejects 400 calories to the sink percycle.

If the effiency of a carnot engine is 25% and the temperature of the source is 327 degree c

Then the temperature will be according to the carot engine effiency of 0.3 when the temperature of the sink is 350° k