#### Answer

The monthly payments are $\$405$
The interest is $\$3665$

#### Work Step by Step

We can use this formula to calculate the payments for a loan:
$PMT = \frac{P~(\frac{r}{n})}{[1-(1+\frac{r}{n})^{-nt}~]}$
$PMT$ is the amount of the regular payment
$P$ is the amount of the loan
$r$ is the interest rate
$n$ is the number of payments per year
$t$ is the number of years
Since the down payment is $\$9000$, the amount of the loan is $\$20,635$
$PMT = \frac{P~(\frac{r}{n})}{[1-(1+\frac{r}{n})^{-nt}~]}$
$PMT = \frac{(\$20,635)~(\frac{0.0662}{12})}{[1-(1+\frac{0.0662}{12})^{-(12)(5)}~]}$
$PMT = \$405$
The monthly payments are $\$405$
We can find the total amount paid.
$\$405 \times 60 = \$24,300$
The interest is the difference between the total amount paid and the amount of the loan.
$I = \$24,300 - \$20,635 = \$3665$
The interest is $\$3665$