The director of facilities & maintenance at Kennesaw State University wants to know the present worth of the maintenance costs for an HVAC system. A recent KSU engineering graduate, who designed the system, estimates that the maintenance costs are expected to be zero for the first three years, $2000 in year four, $2500 in year five, and amounts increasing by $500 each year through year 10. At an interest rate of 8% per year compounded semiannually, the value of n to use in the P/G equation is (choose closest answer)