21. A condominium is purchased for $80,000 with a down payment of $12,000 at an annual interest rate of 9% for 15 years. Calculate the unpaid balance after 10 years of making payments.
22. What would be the market value of the condominium in Exercise 21 after 12 years of making payments if the interest rate goes up to 11%? Use the formula method and the table method.