These questions are based on engineering economics

Mr. Dixon bought a house for $550,000 and made a $180,000 down payment. He obtained a 35-year loan for the remaining amount. Payments were made monthly. The nominal annual interest rate was 10%. After 15 years (180 payments) he decided to pay the remaining balance on the loan.

1.What was his monthly loan payment?

2. What must he have paid (in addition to his regular 180th monthly payment) to pay the remaining balance of his loan?