Problem 5 A special-purpose machine is to be purchased at a cost of $20,000. The following table shows the expected annual operating and maintenance cost and the salvage values for each year of the machine's service: Year of Service O&M Costs Market Value $2,500 3,250 4,225 5,493 7,140 $14,400 11,520 9,216 7,373 5,898 If the interest rate is 8%, what is the economic service life for this machine? Use manual calculations to find the economic life