Answer
There are $2162$ trouts after two months.
Work Step by Step
We substitute $p_0 $ into $p_n$ in order to compute $p_1$ and then substitute $p_1 $ into $p_n$ in order to compute $p_2$ .
$p_1=1.03p_{1-1}+20 \\ =1.03\ p_0+20 \\ =(1.03) (2000)+20 \\ =2060+20 \\ =2080$
$p_2=1.03p_{2-1}+20=1.03p_1+20=1.03(2080)+20=2142+20=2162$
Thus, we find that there are $2162$ trouts after two months.
