Frederick took out a 20-year loan for $70,000 at an apr of 2.2%, compounded monthly. approximately how much would he save if he paid it off 9 years early?

Total compounded interest = P (1 + r/n)^(nt) - P
Total compounded interest = 70,000( 1 + 0.022 / 12)^108 - 70,000
Total compounded interest = 70,000(1.001833)^108 - 70,000
Total compounded interest = 85,311.90 - 70,000
Total compounded interest = 15,311.90

answer
He would save $15,311.90