1. **State the problem:** We want to find the year when the value of Sean's car, initially 20000, depreciates to approximately 5000 given a 19% annual depreciation rate.
2. **Formula used:** The value of the car after $t$ years with depreciation rate $r$ is given by:
$$ V = P(1 - r)^t $$
where $P$ is the initial value, $r$ is the depreciation rate, and $t$ is the number of years.
3. **Apply values:** Here, $P = 20000$, $r = 0.19$, and we want $V \approx 5000$.
4. **Set up the equation:**
$$ 5000 = 20000(1 - 0.19)^t $$
$$ 5000 = 20000(0.81)^t $$
5. **Divide both sides by 20000:**
$$ \frac{5000}{20000} = \cancel{\frac{20000}{20000}}(0.81)^t $$
$$ 0.25 = (0.81)^t $$
6. **Take natural logarithm on both sides:**
$$ \ln(0.25) = \ln((0.81)^t) $$
$$ \ln(0.25) = t \ln(0.81) $$
7. **Solve for $t$:**
$$ t = \frac{\ln(0.25)}{\ln(0.81)} $$
8. **Calculate values:**
$$ \ln(0.25) \approx -1.3863 $$
$$ \ln(0.81) \approx -0.2097 $$
9. **Final calculation:**
$$ t \approx \frac{-1.3863}{-0.2097} \approx 6.61 $$
10. **Interpretation:** The value of the car will be closest to 5000 after about 7 years.
**Answer: C 7**
Car Depreciation 0B003B
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