1. **State the problem:** We are given an exponential function modeling bacteria population growth: $$f(x) = 575(1 + 0.40)^x$$ where $x$ is time in hours and $f(x)$ is population in thousands.
2. **Identify the parameters:** The function is of the form $$f(x) = a b^x$$ where:
- $a = 575$ represents the initial population (at $x=0$).
- $b = 1 + 0.40 = 1.40$ represents the growth factor per hour.
3. **Interpret $a$:** Since $a = 575$, the initial population is $$575 \times 1000 = 575,000$$ bacteria.
4. **Interpret $b$:** The growth factor $b = 1.40$ means the population increases by 40% each hour.
5. **Calculate the growth rate as a percentage:** The growth rate is $$(b - 1) \times 100 = (1.40 - 1) \times 100 = 40\%$$ per hour.
6. **Check the statement about 140% growth:** The statement "population is increasing at a rate of 140% per hour" is incorrect because 140% growth would mean $b = 2.40$ (since $1 + 1.40 = 2.40$).
7. **Summary:**
- Initial population: 575,000 bacteria.
- Growth rate: 40% per hour.
**Final answer:** The initial population was 575,000 bacteria, and the population increases by 40% each hour, not 140%.
Exponential Growth C157D1
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