The total 4-year out of pocket expense is $160K for installs and maintenance. Discounted at 10%, the present value of this expense is $137,365
FV Actual Cost PV Cost
Y0 = 50,000 50,000.00
Y1 = 10,000 9090.91
Y2 = 60,000 49,586.78
Y3 = 20,000 15,026.30...