Derek borrows $284,857.00 to buy a house. He has a 30-year mortgage with a rate of 5.33%. After making 113.00 payments, how much does he owe on the mortgage?

3 answers

To find out how much Derek owes on his mortgage after making 113 payments, we can use the remaining balance formula for a fixed-rate mortgage.

The formula for the remaining balance \( B \) after \( n \) payments is:

\[ B = P \times \frac{(1 + r)^N - (1 + r)^n}{(1 + r)^N - 1} \]

Where:

  • \( B \) is the remaining balance on the mortgage.
  • \( P \) is the original loan amount (the principal), which is $284,857.00.
  • \( r \) is the monthly interest rate (annual interest rate divided by 12).
  • \( N \) is the total number of payments (loan term in months).
  • \( n \) is the number of payments made.

Step 1: Calculate the monthly interest rate

The annual interest rate is 5.33%, so the monthly interest rate \( r \) is:

\[ r = \frac{5.33%}{100} \div 12 = \frac{0.0533}{12} \approx 0.00444167 \]

Step 2: Determine the total number of payments

For a 30-year mortgage, the total number of payments \( N \) is:

\[ N = 30 \times 12 = 360 \]

Step 3: Plug the values into the formula

Where \( n = 113 \):

\[ B = 284,857 \times \frac{(1 + 0.00444167)^{360} - (1 + 0.00444167)^{113}}{(1 + 0.00444167)^{360} - 1} \]

Step 4: Calculate the parts of the formula

Calculate \( (1 + r)^{360} \) and \( (1 + r)^{113} \)

  1. \( (1 + 0.00444167)^{360} \)

\[ (1 + 0.00444167)^{360} \approx 5.250690017 \]

  1. \( (1 + 0.00444167)^{113} \)

\[ (1 + 0.00444167)^{113} \approx 1.647095048 \]

Step 5: Substitute back into the formula

\[ B = 284,857 \times \frac{5.250690017 - 1.647095048}{5.250690017 - 1} \]

Calculating the numerator and denominator:

  • Numerator: \( 5.250690017 - 1.647095048 \approx 3.603594969 \)
  • Denominator: \( 5.250690017 - 1 \approx 4.250690017 \)

So the formula now looks like this:

\[ B = 284,857 \times \frac{3.603594969}{4.250690017} \approx 284,857 \times 0.847291229 \]

Step 6: Calculate the remaining balance

\[ B \approx 241,144.6584 \]

Hence, after making 113 payments, the amount Derek owes on the mortgage is approximately $241,144.66.

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