Original Loan Amount $450,000$

Interest Rate $8\mathrm{.}50\%$ Annual

Term $30$ Years

For the simple contant monthly payment loan above calculate

$1.$ What is the monthly payment $$3,460\mathrm{.}11$

$2.$ How much interest will be paid in the $15$th payment $(4,298\mathrm{.}27)$

$3.$ What is the payoff amount after making payments for $20$ years? $279,073\mathrm{.}39$