1. **State the problem:**
We have a total investment of 20000 split into two parts: one part invested at 11% simple interest for 2 years, and the other part invested at 8% simple interest for 3 years. The total interest earned from both investments is 4690. We need to find how much was invested at 11%.
2. **Define variables:**
Let $x$ be the amount invested at 11%.
Then, the amount invested at 8% is $20000 - x$.
3. **Recall the simple interest formula:**
$$\text{Simple Interest} = P \times r \times t$$
where $P$ is principal, $r$ is rate (in decimal), and $t$ is time in years.
4. **Write the total interest equation:**
Interest from 11% investment:
$$I_1 = x \times 0.11 \times 2 = 0.22x$$
Interest from 8% investment:
$$I_2 = (20000 - x) \times 0.08 \times 3 = 0.24(20000 - x)$$
Total interest:
$$I_1 + I_2 = 4690$$
5. **Set up the equation:**
$$0.22x + 0.24(20000 - x) = 4690$$
6. **Expand and simplify:**
$$0.22x + 4800 - 0.24x = 4690$$
7. **Combine like terms:**
$$0.22x - 0.24x + 4800 = 4690$$
$$-0.02x + 4800 = 4690$$
8. **Isolate $x$:**
$$-0.02x = 4690 - 4800$$
$$-0.02x = -110$$
9. **Divide both sides by -0.02:**
$$x = \frac{-110}{-0.02}$$
Show cancellation:
$$x = \frac{\cancel{-110}}{\cancel{-0.02}} = 5500$$
10. **Answer:**
The amount invested at 11% is **5500**.
Simple Interest 945A64
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