A $100,000 Mortgage at 6

Short Answer

A $100,000 mortgage at 6.75% compounded semi-annually with a 20-year amortization requires monthly payments. The mortgage allows the borrower to miss a payment once each year. How much will the amortization period be lengthened if the borrower misses the ninth payment? (The interest that accrues during the ninth month is converted to principal at the end of the ninth month.)