1. **State the problem:** We have the function $$f(x) = \frac{68.35}{1 + 0.036e^{-0.117x}}$$ modeling the percent of women in the labor force, where $x$ is years since 1950.
2. **Part (a):** Find the percent of women in 2012.
- Calculate $x$ for 2012: $$x = 2012 - 1950 = 62$$
- Substitute into the function:
$$f(62) = \frac{68.35}{1 + 0.036e^{-0.117 \times 62}}$$
3. **Evaluate the exponent:**
$$-0.117 \times 62 = -7.254$$
4. **Calculate $e^{-7.254}$:**
$$e^{-7.254} \approx 0.00071$$
5. **Calculate denominator:**
$$1 + 0.036 \times 0.00071 = 1 + 0.00002556 = 1.00002556$$
6. **Calculate $f(62)$:**
$$f(62) = \frac{68.35}{1.00002556} \approx 68.348$$
7. **Round to nearest whole number:**
$$\boxed{68\%}$$
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8. **Part (b):** Find the year when women made up 30% of the labor force.
- Set $f(x) = 30$:
$$30 = \frac{68.35}{1 + 0.036e^{-0.117x}}$$
9. **Solve for the denominator:**
$$1 + 0.036e^{-0.117x} = \frac{68.35}{30} = 2.2783$$
10. **Isolate the exponential term:**
$$0.036e^{-0.117x} = 2.2783 - 1 = 1.2783$$
11. **Divide both sides by 0.036:**
$$e^{-0.117x} = \frac{1.2783}{0.036} = 35.5083$$
12. **Take natural logarithm:**
$$-0.117x = \ln(35.5083)$$
13. **Calculate the logarithm:**
$$\ln(35.5083) \approx 3.569$$
14. **Solve for $x$:**
$$x = \frac{-3.569}{0.117} = -30.5$$
15. **Interpret $x$:** Negative $x$ means before 1950.
16. **Calculate the year:**
$$1950 + (-30.5) = 1919.5 \approx 1920$$
**Final answers:**
- (a) In 2012, women composed approximately $\boxed{68\%}$ of the labor force.
- (b) Women made up 30% of the labor force around the year $\boxed{1920}$.
Labor Force Women 79E964
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