Let X be a random variable with the following probability distribution. Value x of X P(X-x) 20 0.10 30 0.15 40 0.60 50 0.10 60 0.05 Complete the following. (If necessary, consult a list of formulas.) (a) Find the expectation E (X ) of X. X E(X) = 1 (b) Find the variance Var(X) of X. Var (x) = [