Credit Card Payment
1. **State the problem:** You have a credit card balance of $2000 with an annual interest rate of 13%. You want to pay off the balance in 3 years by making equal monthly payments. We need to find the monthly payment amount.
2. **Formula used:** The monthly payment for a loan with principal $P$, monthly interest rate $r$, and number of payments $n$ is given by the amortization formula:
$$ M = P \times \frac{r(1+r)^n}{(1+r)^n - 1} $$
where:
- $M$ is the monthly payment,
- $P = 2000$ is the principal,
- $r = \frac{0.13}{12}$ is the monthly interest rate (annual rate divided by 12),
- $n = 3 \times 12 = 36$ is the total number of monthly payments.
3. **Calculate monthly interest rate:**
$$ r = \frac{0.13}{12} = 0.0108333... $$
4. **Calculate $(1+r)^n$:**
$$ (1 + 0.0108333)^{36} = (1.0108333)^{36} \approx 1.448 \text{ (rounded)} $$
5. **Calculate numerator and denominator:**
Numerator:
$$ r \times (1+r)^n = 0.0108333 \times 1.448 = 0.01569 $$
Denominator:
$$ (1+r)^n - 1 = 1.448 - 1 = 0.448 $$
6. **Calculate monthly payment $M$:**
$$ M = 2000 \times \frac{0.01569}{0.448} = 2000 \times 0.035 \approx 70.00 $$
7. **Interpretation:** You need to pay approximately $70.00 each month for 3 years to pay off the $2000 balance at 13% annual interest.
**Final answer:**
$$ \boxed{70.00} $$