To determine how much Derek owes on his mortgage after making 144 payments, we need to calculate the remaining balance on the mortgage after these payments have been made. This can be done using the formula for the remaining balance on a fixed-rate mortgage.
The formula for the remaining balance \( B \) after \( n \) payments can be expressed as:
\[ B = P \times \frac{(1 + r)^N - (1 + r)^n}{(1 + r)^N - 1} \]
Where:
- \( B \) is the remaining balance
- \( P \) is the original loan amount (principal)
- \( r \) is the monthly interest rate (annual rate / 12)
- \( N \) is the total number of payments (loan term in months)
- \( n \) is the number of payments already made
Given:
- \( P = 255,011.00 \)
- Annual interest rate = 5.16%, thus the monthly interest rate \( r = \frac{5.16%}{12} = \frac{0.0516}{12} \approx 0.0043 \)
- Total number of payments \( N = 30 \times 12 = 360 \)
- Number of payments made \( n = 144 \)
Now, we can plug in the values into the formula.
Step 1: Calculate the monthly interest rate 'r'
\[ r = \frac{5.16}{100} \div 12 \approx 0.0043 \]
Step 2: Substitute into the balance formula
Now substituting the values into the formula:
\[ B = 255,011.00 \times \frac{(1 + 0.0043)^{360} - (1 + 0.0043)^{144}}{(1 + 0.0043)^{360} - 1} \]
Step 3: Calculate \( (1 + r)^{360} \) and \( (1 + r)^{144} \)
- Calculate \( (1 + r)^{360} \): \[ (1 + 0.0043)^{360} \approx 4.4676 \]
- Calculate \( (1 + r)^{144} \): \[ (1 + 0.0043)^{144} \approx 1.7033 \]
Step 4: Calculate the remaining balance
Now substituting these values:
\[ B = 255,011.00 \times \frac{4.4676 - 1.7033}{4.4676 - 1} \]
Calculating the numerator and denominator:
- Numerator: \( 4.4676 - 1.7033 \approx 2.7643 \)
- Denominator: \( 4.4676 - 1 \approx 3.4676 \)
Thus:
\[ B = 255,011.00 \times \frac{2.7643}{3.4676} \approx 255,011.00 \times 0.7973 \approx 203,144.92 \]
Final Answer
After making 144 payments, Derek owes approximately $203,144.92 on his mortgage.