Answer:
Annual cost = −64,083
Step-by-step explanation:
Present maintenance costs = $180000
Maintenance costs after three years = $70000
Real interest rate = 9%
Inflation rate = 3%
Inflation adjusted interest rate, r = 0.09 + 0.03 + (0.09)(0.03) = 12.27% per year
Annual cost = −180,000(A/P,12.27%,5) –70,000(P/F,12.27%,3)(A/P,12.27%,5)
Annual cost = −180,000(0.27927)–70,000(0.70666)(0.27927)
Annual cost = −64,083