# Write an exponential function to model the following situation: A population starting at 740 animals decreases at an annual rate of 12

Question

Write an exponential function to model the following situation: A population starting at 740 animals
decreases at an annual rate of 12%. Use your function to determine about how many animals there will
be after 5 years.
A. 390
B. 150
CC. 680
D. 340

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1 year 2021-09-02T02:19:12+00:00 1 Answers 6 views 0

An exponential function can be written in the form $$f(n)=a\times b^n$$, where $$a$$ is your starting population, $$b$$ is the factor by which the population increases, and $$n$$ is the number of terms. In this case, $$a=740$$, $$b=0.88$$ because the population decreases by 12 percent (1-0.12=0.88), and $$n=5$$.
Thus, $$f(5)=740 \times 0.88^5$$, which is roughly equal to 390.