A zoologist is investigating the growth of a population of red squirrels in a forest - AQA - A-Level Maths Pure - Question 2 - 2017 - Paper 2

To find the size of the squirrel population at the start of the investigation, substitute $t = 0$ into the equation.

Using the equation:

$N = \frac{200}{1 + 9e^{-\frac{0}{5}}}$

First, evaluate the exponent:

$e^{0} = 1$

Then, substitute this value back into the equation:

$N = \frac{200}{1 + 9 \cdot 1} = \frac{200}{1 + 9} = \frac{200}{10} = 20$

Therefore, the size of the squirrel population at the start of the investigation is 20.