Monthly amortization schedule. Sherry and Sam want to purchase a condo at the coast. They will spend $650,000 on the condo and are taking out a loan for the whole amount for the condo for twenty years at 7.0% interest.

• What is the monthly payment on the mortgage? Construct the amortization of the loan for the twenty years in a spreadsheet to show the interest cost, the principal reduction, and the ending balance each month.
• Then change the amortization to reflect that after ten years, Sherry and Sam will increase their monthly payment to $7,500 per month. When will they fully repay the mortgage with this increased payment if they apply all the extra dollars above the original payment to the principal?