Answer:
[tex]t = 23.10\ years[/tex]
Step-by-step explanation:
We have an exponential decay function:
[tex]A = A_0e ^{-0.03t}[/tex]
This function decreases as the years pass. That is, if A is the quantity for a time t and [tex]A_0[/tex] is the original quantity at time t = 0 then:
[tex]A <A_0[/tex]
We want to know for what value of t the value of A decreases by half of [tex]A_0[/tex]. That is, we want to know when [tex]A = \frac{A_0}{2}[/tex]
Then we do:
[tex]\frac{A_0}{2} = A_0e ^{-0.03t}\\\\\frac{1}{2} =e ^{-0.03t}\\\\ln(\frac{1}{2}) = -0.03t\\\\t = \frac{ln(\frac{1}{2})}{-0.03}[/tex]
[tex]t = 23.10\ years[/tex]