Question: Sharette took out a $1,280, 6-year loan with an APR of 8.15% to buy a new computer.
a. What is the monthly payment? The monthly payment is $
$.
b. At the end of the 6-year term, how much money will she have paid for the computer? She will have paid $
$.
c. What is the interest charge? The interest charge is $
$.
1. **State the problem:** Sharette took out a loan of $1280$ dollars for $6$ years with an APR of $8.15\%$. We need to find:
a. The monthly payment.
b. The total amount paid after 6 years.
c. The interest charged.
2. **Formula for monthly payment on an installment loan:**
$$M = P \times \frac{r(1+r)^n}{(1+r)^n - 1}$$
where:
- $M$ is the monthly payment,
- $P$ is the principal amount ($1280$),
- $r$ is the monthly interest rate (APR divided by 12),
- $n$ is the total number of payments (months).
3. **Calculate monthly interest rate $r$ and total payments $n$: **
$$r = \frac{8.15}{100 \times 12} = \frac{8.15}{1200} = 0.0067917$$
$$n = 6 \times 12 = 72$$
4. **Calculate $(1+r)^n$: **
$$ (1 + 0.0067917)^{72} = 1.0067917^{72} \approx 1.60103$$
5. **Calculate numerator and denominator for the formula:**
Numerator:
$$r(1+r)^n = 0.0067917 \times 1.60103 = 0.01087$$
Denominator:
$$(1+r)^n - 1 = 1.60103 - 1 = 0.60103$$
6. **Calculate monthly payment $M$: **
$$M = 1280 \times \frac{0.01087}{0.60103} = 1280 \times 0.01809 = 23.16$$
7. **Calculate total amount paid over 6 years: **
$$\text{Total paid} = M \times n = 23.16 \times 72 = 1667.52$$
8. **Calculate interest charged: **
$$\text{Interest} = \text{Total paid} - \text{Principal} = 1667.52 - 1280 = 387.52$$
**Final answers:**
- a. Monthly payment is $\boxed{23.16}$.
- b. Total amount paid is $\boxed{1667.52}$.
- c. Interest charged is $\boxed{387.52}$.