1. The problem statement, all variables and given/known data A system consists of three bodies with the same heat capacity. These are initially at 200 K,400 K and 400 K respectively. Show that, without the supply of any mechanical energy or heat from outside the system, the highest temperature to which any of the bodies can be raised by operating heat engines between them is 488 K. 2. Relevant equations efficiency = 1- (Tc/Th) dU=dQ-dW 3. The attempt at a solution I believe the solution may have something to do with the work lost in one heat engine being used as useful work in another.