Please answer a and b

Let X be a random variable with the following probability distribution. Value x of X P ( X=x) 40 0.15 50 0.10 60 0.40 70 0.25 80 0.05 90 0.05 Complete the following. (If necessary, consult a list of formulas.) (a) Find the expectation E (X ) of X. E( X) =[ (b) Find the variance Var(X ) of X. Var (X) = 1