# Math Help - Probability Problem

1. ## Probability Problem

A box contains 12 red and 13 white marbles. If 8 marbles are chosen at random (without replacement) determine the probability that 6 are red. Write your answer as a fraction reduced to lowest terms.

PLease help! I thought I knew what to do but then I just kept confusing myself.

2. Originally Posted by sweeetcaroline
A box contains 12 red and 13 white marbles. If 8 marbles are chosen at random (without replacement) determine the probability that 6 are red. Write your answer as a fraction reduced to lowest terms.
PLease help! I thought I knew what to do but then I just kept confusing myself.
Why not show us what you have done that is confusing you?
We cannot help if we are in the dark.

3. Well I thought that I could use a binomial or geometic model, but that didn't take into account that of 8 chosen probability that 6 are red. And then I thought that maybe somehow using the number of possibilities, figure out how many that has 6 red if 8 are chosen but I wasn't exactly sure how to do that. Am I on the right track with either of these ideas?

4. hypergeometric

${ {12\choose 6}{13\choose 2}\over {25\choose 8}}$