Let X denote the number of Canon SLR cameras sold during a particular week by a certain store. The pmf of X is Fifty-five 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. x 0 1 2 3 4
px(x) 0.1 0.2 0.3 0.25 0.15

Required:
a. What is P(X = 4, Y = 2)?
b. Calculate P(X = Y).