Question

The number of trees in a rainforest decreases each month by 0.5%. The forest currently has 2.5 billion trees. Which expression represents how many trees will be left in 10 years. Group of answer choices

Answer 1

`y=2.5*10^9(0.005^(12 0)) \\\\`

Explanation:

The above question is in the form of an exponential decay. The equation for an exponential decay is given by:

`y=ab^x`

where y and x are variables, b < 1, a is the initial value of y (that is the value of y when x = 0).

Let y represent the number of trees left and x represent the number of months. Given that there is currently 2.5 billion trees, therefore a = 2.5 * 10⁹, b = 0.5% = 0.005. The equations becomes:

`y=2.5*10^9(0.005^x)\\\\After\ ten\ years(x=10*12\ months=120\ months):\\\\y=2.5*10^9(0.005^(12 0)) \\\\`