P= F(1+i) P = (A/i) (1-(1+i)n] A = (Pi)/(1-(1+i)n] The net present value of an investment to purchase a solar PV system that costs $10,000 and saves $2,400 per year for 20 years, and will increase the cost of reroofing by $7,000 in year 15, if your next best investment is 5% per year is about: O $ 14,542 0 $ 10,046 O $ 12,914 O $ 8,256