posted by matt on .
Kevin has 11 CDs in his glove compartment. Six are rock and 5 are rap. He selects 3 cds at random.
What is the probability that he picks at least 2 rap cds?
Pr (two)=5/11 * 4/10 * 6/9
Pr (three ) =5/11 * 4/10 * 3/9
Not quite bobpursley.
There are 3 ways to pick 2 rap cds: (rap,rap,rock),(rap,rock,rap), and (rock,rap,rap). So,
Pr(two)=3*(5/11 * 4/10 * 6/9)
Pr(three) = same as before