Final answer:
The total cost of the 15-year, $20,000 student loan at an interest rate of 4.5% per year compounded monthly is approximately $4,969,354.67.
Step-by-step explanation:
To calculate the total cost of a 15-year, $20,000 student loan at an interest rate of 4.5% per year compounded monthly, we can use the formula for the future value of an ordinary annuity:
FV = P * [(1 + r/n)^(n*t) - 1] / (r/n)
Where:
- FV = Future value
- P = Principal (initial amount)
- r = Annual interest rate (as a decimal)
- n = Number of compounding periods per year
- t = Number of years
Plugging in the values from the question, we get:
FV = $20,000 * [(1 + 0.045/12)^(12*15) - 1] / (0.045/12)
FV ≈ $20,000 * (1.00375^(180) - 1) / (0.00375)
FV ≈ $20,000 * (1.931726 - 1) / (0.00375)
FV ≈ $20,000 * 0.931726 / 0.00375
FV ≈ $20,000 * 248.4677333
FV ≈ $4,969,354.67
So, the total cost of the loan is approximately $4,969,354.67.