How Much Energy Input Is Needed for an Engine to Perform 10.2 kJ of Work?

[VelvetRebel]

Homework Statement

A heat engine operating between 78.5oC and 204oC achieves 20.6% of the maximum possible efficiency. What energy input will enable the engine to perform 10.2 kJ of work?

The only help I need with this is exactly what equation(s) to use. I would think thermal efficiency would be one equation(e=W/Q_h) but not sure what else to use.

 

[kjohnson]

You need to take a look at the carnot efficiency of the heat engine, this will tell you the maximum possible work for a heat engine operating between two temperature resivors.