Question

Which equation describes the town’s population in terms of years (x)?

Answer 1

In general, the exponential growth formula is

$f(x)=a(1+r)^x$

Where a is the initial amount, r is the growth/shrinking rate and x is the number of time intervals. In our case,

$\begin{gathered} a=18000 \\ r=-0.03 \\ \Rightarrow f(x)=y=18000(1-0.03)^x=18000(0.97)^x \\ \Rightarrow y=18000(0.97)^x \end{gathered}$

The answer is y=18000(0.97)^x, fourth option top to bottom.