Question 931189
Let X be the random variable that takes on the values 5, 8, 2.  Then,
P(X=5) = 2/10 = 1/5, P(X=8) = 3/10, P(X=2) = 5/10 = 1/2
E(X) = 2*1/5 + 3*3/10 + 5*1/2 = 4/10 + 3/10 + 25/10 = 32/10 = $3.20