A couple buys a $200000 home, making a down payment of 17%. The couple finances the purchase with a 15 year mortgage at an annual rate of 3.84%. Find the monthly payment. If the couple decides to increase the monthly payment to $1300, find the number of payments.

Respuesta :

First, we calculate how much is 17% of the home cost $200,00. For this, we divide 200,000 by 100 and then multiply by 17:

[tex]\frac{200,000}{100}\times17=34,000[/tex]

The down payment was $34,000

So we subtract this amount from the total amount of the home:

[tex]200,000-34,000=166,000[/tex]

They still need to pay $166,000.

Now we use the mortgage formula to calculate the monthly payments "M":

[tex]\begin{gathered} M=P\times\frac{r(1+r)^n}{(1+r^{})^n-1} \\ \end{gathered}[/tex]

Where P is the principal or the amount borrowed. In this case:

[tex]P=166,000[/tex]

n is the number of payments. Since the payments are monthly for 15 years, and each year has 12 months. The amount of payments n is:

[tex]n=15\times12=180[/tex]

And r is the interest rate divided by 12. The interest rate is 3.84% which in decimal is 0.0384. Thus, the value of r is:

[tex]r=\frac{0.0384}{12}=0.0032[/tex]

We substitute all of these values into the formula:

[tex]M=166,000\times\frac{0.0032(1+0.0032)^{180}}{(1+0.0032)^{180}-1}[/tex]

Solving the operations to find M:

[tex]\begin{gathered} M=166,000\times\frac{0.0032(1.0032)^{180}}{(1.0032)^{180}-1} \\ M=166,000\times\frac{0.0032(1.7773)^{}}{1.7773^{}-1} \\ M=166,000\times\frac{5.687\times10^{-3}^{}}{0.7773^{}} \\ M=1,214.57 \end{gathered}[/tex]

The monthly payments: $1,214.57

If they increase the monthly payment to 1300, we need to divide the 166,000 by 1,300 to find the number of payments they have to make:

[tex]\frac{166,000}{1300}=127.7[/tex]

The number of payments: 127.7