Assume that there are 6 different
issues of Sports Illustrated, 7 different issues
of Time, and 3 different issues of Newsweek, including the December 1st issue, on the rack. You
choose 4 of them at random.
(1) What is the probability that exactly 1 is an
issue issue of Sports Illustrated?
(2) What is the probability that you choose the
December 1st issue of Newsweek?

Question

Assume that there are 6 different
issues of Sports Illustrated, 7 different issues
of Time, and 3 different issues of Newsweek, including the December 1st issue, on the rack. You
choose 4 of them at random.
(1) What is the probability that exactly 1 is an
issue issue of Sports Illustrated?
(2) What is the probability that you choose the
December 1st issue of Newsweek?

directrix · Answer

(1) [C(6,1) C(10,3)] / C(16,4) = 36/91 = .396 approx

directrix · Answer

(2)  [C(1,1) C(15,3)] / C(16,4) = 1/4 = .25