$Q^{\text{u}\text{e}\text{s}\text{t}\text{i}\text{o}\text{n}}-$

Let $x_1,x_2,x_3$ be independent random variables with $n_1=15,p_1=0\mathrm{.}6$;$n_2=200\mathrm{.}6$ and $n_3=25,p_3=0\mathrm{.}6$ respectively. Let $Y=x_1+x_2+,x_3.$

$($a$)$ Find the MGF of $Y$

$($b$)$ From the MGF Find E$($Y$)$ and VAR $($Y$)$