Let X denote the number of Canon SLR cameras sold during a p

Let X denote the number of Canon SLR cameras sold during a particular week by a certain store. The pmf of X is

Sixty percent of all customers who purchase these cameras also buy an extended warranty. Let Y denote the number of purchasers during this week who buy an extended warranty.

(a) What is P(X = 4, Y = 2)? [Hint: This probability equals

P(Y = 2|X = 4) · P(X = 4);

now think of the four purchases as four trials of a binomial experiment, with success on a trial corresponding to buying an extended warranty.] (Round your answer to four decimal places.)
P(X = 4, Y = 2) =  

(b) Calculate P(X = Y). (Round your answer to four decimal places.)
P(X = Y) =  

(c) Determine the joint pmf of X and Y.

(0.6)^x(0.6)^xy · p_X(x)

(0.6)^y(0.6)^xy · p_X(x)    

(0.6)^y(0.4)^xy · p_X(x)

(0.6)^x(0.4)^xy · p_X(x)
Determine the marginal pmf of Y. (Round your answers to four decimal places.)

Solution