UNO High School Problem of the Week Competition
Problem 6
Thirteen cards are selected from a deck of 52 cards. What is the probability that at least two will be spades. (Assume four distinct suits per deck)
Solution
The probability will be 1-probability of no spades-the probability of 1 spades.
That is 1-(C(39,13)/C(52,13))-((C(13,1)*C(39,12))/C(52,13)) = .90715.
Thus the probablity that at least two are spades is 90.715%.
