The number of mat students working in the student club office can be represented as a random variable X, with the following probability distribution:

f(x) = {.10 x = 0}

f(x) = {.25 x = 1}

f(x) = {.40 x = 2}

f(x) = {.25 x =3}

(a) What is the probability that at least 3 students are in the student club office?

(b) What is the expected value of X?