500
In a drawer with 4 gray socks, 6 white socks and 2 black socks, what is the probability you will pull out 2 socks that match? (you do NOT replace the sock after the first pull)
Matching grays: 4/12 * 3/11 = 1/11
Matching whites: 6/12 * 5/11 = 5/22
Matching blacks: 2/12 * 1/11 = 1/66
1/11 + 5/22 + 1/66 = 22/66 = 1/3