The per capita electrical power consumption in the United States is about 200. kW · h/d. Suppose this power is generated by having mice run in wheels that turn electrical generators. These mice are to be feed Swiss cheese that has a metabolizable energy content of 15.5 MJ/kg and costs $4.00 per kilogram.
If the mice have an energy conversion efficiency of 25.0%, how much will it cost to buy the cheese needed to feed the mice who supply the per capita energy needs?