The power W dissipated in a resistor is proportional to the square of the voltage V. That is,
$W = rV^2$
where r is a constant. If $r = 3$, and V can be assumed (to a very good approximation) to be a
normal random variable with mean $\mu = 6$ and standard deviation $\sigma = 1$, find
a. E[W]
b. P(W > 120)