Final answer:
To answer the student's questions on mortgage payments and interest, calculate the monthly payment using the loan formula, then analyze an amortization schedule for interest and principal breakdown at specified payments. The total interest paid is the sum of all interest payments over the life of the mortgage.
Step-by-step explanation:
To calculate the monthly payments and interest over the life of the mortgage, the student should use the following formula for an amortizing loan's regular payment amount:
PMT = P * r(1+r)^n / ((1+r)^n - 1)
Where:
PMT is the monthly payment
P is the principal amount (after down payment)
r is the monthly interest rate (annual rate divided by 12)
n is the total number of payments (months for the life of the loan)
For part a), the student will calculate the monthly payment using the mortgage amount after the 20% down payment, with a 7.85% annual interest rate, over 15 years (180 payments).
For parts b) and c), the student will need to analyze the amortization schedule to determine specific amounts of interest and principal paid at different stages of the mortgage.
Finally, for part d), the student will sum all interest payments over the life of the mortgage, which can be calculated directly from the mortgage payment and the number of payments, or derived from the amortization schedule.