Question: Find the interest earned on a $30,000 deposit for six months at 1 1/2 % interest, compounded continuously.
1. **State the problem:** We need to find the interest earned on a principal amount of $30000$ deposited for $6$ months at an interest rate of $1 \frac{1}{2} \%$ per year, compounded continuously.
2. **Formula used:** For continuous compounding, the amount $A$ after time $t$ years is given by:
$$A = P e^{rt}$$
where:
- $P$ is the principal
- $r$ is the annual interest rate (in decimal)
- $t$ is the time in years
- $e$ is Euler's number (approximately $2.71828$)
3. **Convert given values:**
- Principal $P = 30000$
- Interest rate $r = 1 \frac{1}{2} \% = 1.5\% = 0.015$
- Time $t = 6$ months $= \frac{6}{12} = 0.5$ years
4. **Calculate the amount $A$:**
$$A = 30000 \times e^{0.015 \times 0.5} = 30000 \times e^{0.0075}$$
5. **Evaluate $e^{0.0075}$:**
Using a calculator or approximation,
$$e^{0.0075} \approx 1.00753$$
6. **Calculate $A$:**
$$A = 30000 \times 1.00753 = 30225.9$$
7. **Find the interest earned:**
Interest $I = A - P = 30225.9 - 30000 = 225.9$
**Final answer:** The interest earned is approximately $225.90$.