A used machine costs $20 000 to purchase. It has an annual maintenance cost of $20 000, a sal of $5000, and a 10-year life. If the interest rate is 10% per year, compounded annually, w present-worth cost of the machine? Ans. $140 960.12 vage value hat is the 896 per vear 7.16 Rework Problem 7.6 for