5. Let X denote the number of Canon SLR cameras sold during a particular week by a certain store. The pmf of X is X Px(x) 0 1 2 3 4 .1 2 .3 .25 .15 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.] b. Calculate P(X = Y). c. Determine the joint pmf of X and Y and then the marginal pmf of Y.