40. The engineering department at a leading university decides to implement an energy-saving program by reducing its usage of electricity for lighting and heating the department buildings. The department wants to save $300,000 at the end of 3 years.

Electricity costs $0.25/kWh. (4.7)

a. By how much must annual electricity be reduced to meet the savings goal? Assume uniform annual electricity consumption and a 0% interest rate.

b. Repeat Part

(a) when the annual interest rate is 10%.

c. Why is the answer to Part

(b) less than the answer to Part (a)?