1. **Stating the problem:**
George takes out a loan of £7500 that gathers compound interest. We are given the loan values after 1 and 2 years and need to find:
a) The annual interest rate as a percentage to 1 decimal place.
b) The value of the loan after 10 years, rounded to the nearest penny.
2. **Formula used:**
The compound interest formula is:
$$ A = P(1 + r)^t $$
where:
- $A$ is the amount after $t$ years,
- $P$ is the principal (initial amount),
- $r$ is the annual interest rate (as a decimal),
- $t$ is the time in years.
3. **Finding the interest rate $r$:**
From the table:
- $P = 7500$
- After 1 year, $A = 7905$
Using the formula for $t=1$:
$$ 7905 = 7500(1 + r)^1 $$
Divide both sides by 7500:
$$ 1 + r = \frac{7905}{7500} = 1.054 $$
So,
$$ r = 1.054 - 1 = 0.054 $$
Convert to percentage:
$$ r = 0.054 \times 100 = 5.4\% $$
4. **Check with year 2 value:**
Using $r=0.054$ and $t=2$:
$$ A = 7500(1.054)^2 = 7500 \times 1.110916 = 8331.87 $$
This matches the given value, confirming our rate.
5. **Calculate the loan value after 10 years:**
Using $r=0.054$ and $t=10$:
$$ A = 7500(1.054)^{10} $$
Calculate $(1.054)^{10}$:
$$ (1.054)^{10} \approx 1.708 \quad \text{(using a calculator)} $$
So,
$$ A = 7500 \times 1.708 = 12810.00 $$
Rounded to the nearest penny, the loan value after 10 years is £12810.00.
**Final answers:**
- a) Interest rate = 5.4% per annum
- b) Loan value after 10 years = 12810.00 pounds
Compound Interest 8E930E
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