Answer:
[tex]y=2.5*10^9(0.005^{12 0}) \\\\[/tex]
Step-by-step explanation:
The above question is in the form of an exponential decay. The equation for an exponential decay is given by:
[tex]y=ab^x[/tex]
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:
[tex]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}) \\\\[/tex]
