91Ó°ÊÓ

Given, that in1980, thepopulation of alligatorson the Kennedy Space Center groundswas estimated to be 1500 and it was estimated to be 6000 in 2006. We have to find the estimated population of alligators in the year 2020 by using Malthusian law for population growth and the formula for this is,

$\mathit{p}\mathbf{\left(}\mathbf{t}\mathbf{\right)}\mathbf{=}{\mathit{p}}_{\mathbf{0}}{\mathit{e}}^{\mathbf{kt}}\mathbf{·}\mathbf{·}\mathbf{·}\mathbf{·}\mathbf{·}\mathbf{·}\mathbf{\left(}\mathbf{1}\mathbf{\right)}$

where p(t) is the population at time t, p₀ is the initial population and k is a constant.

If we set t = 0 to be the year1980,then by formula(1),

$\mathit{p}\mathbf{\left(}\mathbf{t}\mathbf{\right)}\mathbf{=}\mathbf{\left(}\mathbf{1500}\mathbf{\right)}{\mathit{e}}^{\mathbf{kt}}\mathbf{·}\mathbf{·}\mathbf{·}\mathbf{·}\mathbf{·}\mathbf{·}\mathbf{\left(}\mathbf{2}\mathbf{\right)}$

where p(t) is the population of alligators at a time t.

The population of splake in the lake was estimated to be 6000 in 2006 and the difference between the years 1980 and 2006 is 26years. Therefore,

$\mathit{p}\mathbf{\left(}\mathbf{26}\mathbf{\right)}\mathbf{=}\mathbf{6000}$

Now in equation (2), if we put t=26, then

$$\begin{gathered} p\left(26\right)=\left(1500\right)e^{26k} \\ 6000=\left(1500\right)e^{26k} \\ \frac{6000}{1500}=e^{26k} \\ {e}^{26k}=4 \\ 26k=\ln 4 \\ k=\frac{\ln 4}{26} \\ k=0.05332 \end{gathered}$$

One will use this value of k, to find the estimated value of the population of alligators on the Kennedy Space Center grounds in the year 2020.

Now as the difference between the years 2006 and 2020 is 14years, and (from step 3), here we will take 2006 as the initial year ie. we will substitute ${\mathit{p}}_{\mathbf{0}}\mathbf{=}\mathbf{6000}$in (1). Therefore,

$$\begin{gathered} \mathit{p}\left(14\right)\mathbf{=}\left(6000\right){\mathit{e}}^{\left(14\right)\left(0.05332\right)} \\ \mathit{p}\left(14\right)\mathbf{=}\left(6000\right){\mathit{e}}^{\mathbf{0}\mathbf{.}\mathbf{74648}} \\ \mathit{p}\left(14\right)\mathbf{=}\mathbf{12657} \end{gathered}$$

Hence, theestimated value of the population of alligators on the Kennedy Space Center grounds in the year 2020 is 12657.