1) A $20,000 loan with annual interest of 7.5% for 8 years will amount to $117,146 total. 2) A 30-year $125,000 loan with 9% interest will have monthly payments of $1,006. 3) It will take 123 months (10 years) to retire a $100,000 loan with monthly payments of $500 and annual interest of 8.75%.