Question

A scientist is studying wildlife. She estimates the population of bats in her state to be 345,000. She predicts the population to grow at an average annual rate of 1.2%. Using the scientist’s prediction, create an equation that models the population of bats, y, after x years.

y=345,000(0.012)^x
y=345,000(0.988)^x
y=345,000(1.012)^x
y=345,000(1.2)^x

Answer 1

Explanation:

the other answer is correct.

I just want to point out some mechanism used here :

the increase by 1.2%

an increase by x% means adding x% to the original 100%.

so, we end up with (100 + x)%.

"%" just stands for 1/100.

so, if y = 100%, an increase by x% is

y×(100 + x)/100 = y×(1 + x/100)

in our case here that is

345,000 × (1 + 0.012) = 345,000 × 1.012

and since the increase rate of 1.2% applies per year, we multiply the end population of every year by 1.012 for the following year.

so, each year a new factor of 1.012 is being integrated into the calculation.

it goes then

345,000×1.012×1.012×1.012×...×1.012 x times after x years.

and we get

y = 345,000 × (1.012)^x

Answer 2

Explanation:

The equation that models the population of bats, y, after x years can be found using the formula:

y = P(1 + r)^x

where P is the initial population, r is the annual growth rate as a decimal, and x is the number of years.

In this case, the initial population P is 345,000, the annual growth rate r is 1.2% or 0.012 as a decimal, and x is the number of years. Substituting these values into the formula, we get:

y = 345,000(1 + 0.012)^x

Simplifying the expression in the parentheses, we get:

y = 345,000(1.012)^x

Therefore, the equation that models the population of bats, y, after x years is:

y = 345,000(1.012)^x