1. **State the problem:**
Rebecca takes out a loan with compound interest. We know the initial amount and the values after 1 and 2 years. We 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 for compound interest:**
The value of the loan after $t$ years is given by:
$$ A = P(1 + r)^t $$
where:
- $A$ is the amount after $t$ years,
- $P$ is the initial principal,
- $r$ is the annual interest rate (as a decimal),
- $t$ is the time in years.
3. **Find the interest rate $r$:**
From the table:
- Start: $P = 2500$
- After 1 year: $A = 2630$
Using the formula for $t=1$:
$$ 2630 = 2500(1 + r)^1 $$
Divide both sides by 2500:
$$ \frac{2630}{2500} = \cancel{\frac{2500}{2500}}(1 + r) $$
$$ 1.052 = 1 + r $$
Subtract 1:
$$ r = 1.052 - 1 = 0.052 $$
Convert to percentage:
$$ r = 0.052 \times 100 = 5.2\% $$
4. **Check with 2 years data:**
Using $r=0.052$ and $t=2$:
$$ A = 2500(1.052)^2 = 2500 \times 1.1067 = 2766.76 $$
This matches the table, confirming our rate.
5. **Calculate value after 10 years:**
Using $r=0.052$ and $t=10$:
$$ A = 2500(1.052)^{10} $$
Calculate $(1.052)^{10}$:
$$ (1.052)^{10} \approx 1.677 $$
So:
$$ A = 2500 \times 1.677 = 4192.5 $$
Rounded to nearest penny:
$$ \boxed{4192.50} $$
**Final answers:**
- a) Interest rate = 5.2% per annum
- b) Value after 10 years = 4192.50 pounds
Compound Interest 02856E
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