A homeowner has $200,000 home with a 20-year mortgage, paid monthly at a quoted interest rate of 7.25% per year compounded semi-annually. After five...

A homeowner has $200,000 home with a 20-year mortgage, paid monthly at a quoted interest rate of 7.25% per year compounded semi-annually. After five years he receives $50,000 as an inheritance. If he pays this $50,000 toward his mortgage along with his regular payment, by approximately how many years will it reduce the amount of time it takes him to pay off his mortgage?