4-60. A company is considering investing $10,000 in a heat exchanger. The heat exchanger will last five years, at which time it will be sold for $2,000. The maintenance cost at the end of the first year is estimated to be $1,000. Maintenance costs for the exchanger are estimated to increase by $500 per year over its life. As an alternative the company may lease the equipment for $X per year, including maintenance. (4.10)

a. Draw a cash-flow diagram of both alternatives.

b. For what value of X should the company lease the heat exchanger? The company expects to earn 8% on its investments. Assume end-of-year lease payments.