(a) The monthly principal and interest payments for each loan are as follows:
- 15-year mortgage: $2,271
- 30-year mortgage: $1,610
(b) The total amount of interest paid on each loan is as follows:
- 15-year mortgage: $88,017
- 30-year mortgage: $256,017
(c) Overall, by choosing the 30-year mortgage, you would pay $168,000 more in interest compared to the 15-year mortgage.
Now, let's break down the calculations step by step:
(a) Monthly Principal and Interest Payments:
To calculate the monthly principal and interest payments, you can use the formula for the monthly payment on a fixed-rate mortgage:
Monthly Payment (M) = P [r(1+r)^n] / [(1+r)^n - 1]
Where:
- P = Loan amount ($300,000)
- r = Monthly interest rate (annual rate / 12 / 100)
- n = Number of monthly payments (15 years = 180 months for the 15-year mortgage and 30 years = 360 months for the 30-year mortgage)
For the 15-year mortgage:
r = 4.5% / 12 / 100 = 0.00375
n = 15 years * 12 months/year = 180 months
M = 300,000 [0.00375(1+0.00375)^180] / [(1+0.00375)^180 - 1]
M ≈ $2,271
For the 30-year mortgage:
r = 5% / 12 / 100 = 0.004167
n = 30 years * 12 months/year = 360 months
M = 300,000 [0.004167(1+0.004167)^360] / [(1+0.004167)^360 - 1]
M ≈ $1,610
(b) Total Amount of Interest Paid:
To find the total amount of interest paid on each loan, you can use the following formula:
Total Interest = (Monthly Payment * Number of Payments) - Loan Amount
For the 15-year mortgage:
Total Interest = ($2,271 * 180) - $300,000
Total Interest ≈ $88,017
For the 30-year mortgage:
Total Interest = ($1,610 * 360) - $300,000
Total Interest ≈ $256,017
(c) To find the overall difference in interest paid, subtract the total interest paid on the 15-year mortgage from the total interest paid on the 30-year mortgage:
Overall Difference = $256,017 (30-year mortgage) - $88,017 (15-year mortgage)
Overall Difference ≈ $168,000
So, choosing the 30-year mortgage would result in paying approximately $168,000 more in interest compared to the 15-year mortgage over the life of the loan.