An ideal Carnot's engine whose efficiency 40% receives heat of 500K. If the efficiency is to be 50% then the temperature of sink will be

In a Carnot engine the temperature of source is 1000 K and the efficiency of engine is 70%. What is the temperature of the sink ?

In carnot engine efficiency is 40% at hot reservoir temperature T. For efficiency to be 50%, what will be the temperature of hot reservoir ?

A carnot engine has an efficiency of 30% .Its efficiency is to beincreased to 50% .By what must the temperature (in K) of the source be increased if the sink is at 300K ?