Let x denote the number of canon slr cameras sold during a particular week by a certain store. the pmf of x is

x | 0 1 2 3 4
px(x) | 0.1 0.2 0.3 0.25 0.15

seventy 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)?
b) calculatep(x=y).
c) determine the joint pmf ofxandy formula
d) determine the marginal pmf ofyas a table.