5. A certain drugstore has three public telephone booths. For i =0, 1, 2, 3, Iet P_i denote the probability that exactly I telephone booths will be occupied on any Monday evening at 8:00 P.M.: and suppose that p_0=0.1,p_(2 )=0.4, and p_3=0.3. Let X andY denote the number of booths that will be occupied at 8:00 P.M. on two independent Monday evenings. Determine: (a) the joint p.f. of X and Y; (b)Pr (X=Y); (c)Pr(X>Y).