Question

Suppose the population of a town is 17,400 and is growing 2% each year.

Predict the population after 9 years.

Answer 1

Answer: 20,532

Explanation:

17,400(.02)=348

348(9)=3132

17,400+3132=20,532

Answer 2

Explanation:

This is an exponential growth function of the form:

`y=ab^x` where a is the initial population and b is the growth rate. This could also be written as

`y=a(1+r)^x` which is a bit more accurate. We'll use that one. r is the percent growth: 2% for us.

Filling in the formula:

`y=17400(1+.02)^x` and then simplifying:

`y=17400(1.02)^x`

That's the model for this population. Filling in any number of years for x will give you the population y. Our time is 9 years:

`y=17400(1.02)^9`

Take care of the exponents first, giving us:

`y=17400(1.195092569)` and then multiply to get

y = 20,794.6 or 20,794 people (since you can't have 6/10 of a person)