Alibrary subscribes to two different weekly news magazines, each of which is supposed to arrive in wednesday's mail. in actuality, each one could arrive on wednesday (w), thursday (t), friday (f), or saturday (s). suppose that the two magazines arrive independently of one another and that for each magazine p(wed.) = .3, p(thurs.) = .4, p(fri.) = .2, and p(sat.) = .1. let y = the number of days beyond wednesday that it takes for both magazines to arrive (so possible y values are 0, 1, 2, or 3). compute the pmf of y.