Answer
0.12
Work Step by Step
First we calculate the probability and the mean
$p=8.25/1000=0.00825$ and $\lambda=np=400\times0.00825=3.3$
Use the Poisson formula $P(X;\lambda)=\frac{e^{-\lambda}\lambda^X}{X!}$ we have
$P(5;3.3)=\frac{e^{-3.3}3.3^5}{5!}=0.12$
