1. **State the problem:** We want to find the compound interest rate given the initial amount and the amounts after 1 and 2 years.
2. **Formula used:** The compound interest formula is $$A = P(1 + r)^t$$ where:
- $A$ is the amount after time $t$
- $P$ is the principal (initial amount)
- $r$ is the annual interest rate (as a decimal)
- $t$ is the time in years
3. **Given values:**
- $P = 2500$
- After 1 year, $A_1 = 2630$
- After 2 years, $A_2 = 2766.76$
4. **Find the interest rate $r$ using the first year data:**
$$2630 = 2500(1 + r)^1$$
Divide both sides by 2500:
$$\frac{2630}{2500} = \cancel{\frac{2500}{2500}}(1 + r)$$
$$1.052 = 1 + r$$
Subtract 1 from both sides:
$$r = 1.052 - 1 = 0.052$$
5. **Verify with the second year data:**
Using $r = 0.052$, calculate amount after 2 years:
$$A_2 = 2500(1 + 0.052)^2 = 2500(1.052)^2 = 2500 \times 1.107704 = 2769.26$$
The given amount is 2766.76, which is very close, confirming the interest rate.
6. **Final answer:** The annual compound interest rate is **5.2%**.
Compound Interest Af6D0D
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