8. (14%) P represents the probability of adverse reaction not happening for a vaccination. P is a random variable with density functions:

$$\left\{ \begin{array}{ll} 12p^2(1-p) & 0 \le p \le 1 \\ 0 & otherwise \end{array} \right.$$

Let n be the number of persons who have been injected. Y is the number of persons that adverse reaction does not happen after vaccination. Please calculate E(Y) if n=10.