A heavy-equipment salesman can contact either one or two customers per day with
probability 1/3 and 2/3, respectively. Each contact will, independently, result in either
no sale or a $50, 000 sale with probability 9/10 and 1/10, respectively.
(a) Find the probability distribution of the daily sales of the salesman.
(b) Find the expected daily sales.
(c) Find the standard deviation of the daily sales.