Answer:
savings per year = $20,500 - $10,500 = $10,000
the loan and interest are not included in the calculation
initial outlay = $50,000
cash flows 1-8 = $10,000
cash flow 9 = $15,000
discount rate = 15%
using a financial calculator, the NPV = -$862.85, and the IRR = 14.53%