Example 4: A company needs to purchase one of the following machines from a vender. Inflation is predicted to be 3% per year for the next 15 years. If a real MARR of 6% is required, which machine should be purchased? The scrap value of both machines in 15 years is zero. f = 0.03 N = 15 MARR = 1 = 0.05 Machine 1 Machine 2 Purchase cost ($) 20,000 25,000 Uniform annual benefit ($) Useful life (yr) 3,000 3,500 15 15