(1) What is the probability that exactly 1 is an issue issue of Newsweek?

Question

Assume that there are 6 different issues of Newsweek, 7 different issues of Sports Illustrated, and 3 different issues of Time, 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 Newsweek?

(2) What is the probability that you choose the December 1st issue of Time?

Answer 1

You've got to love probability.

a)  ₆C₁ * ₁₀C₃  /  ₁₆C₄    I hope you know this notation for combinations. Youy must choose only 1 Newsweek but must                                           choose 4 overall....so you must choose 3 magazines from the non-newsweeks(10) divided

                                    by your choosing any random 4 from the 16 magazines.

b)₁C₁ * ₁₅C₃ / ₁₆C₄        Very similar explanation to above.

 

Hope this helped