A man has 30 identical socks in a drawer. Well, actually they are identical in all respects except colour - twelve are green, ten are white and eight are yellow.
He wants a pair of yellow socks, but is forced to take socks from the drawer in complete darkness.
What is the minimum number of socks that he needs to take from the drawer to ensure he has at least two yellow socks?
He must take 24 socks from the drawer.
If he takes out 22 socks there is a chance, albeit a small chance, that he has the twelve green socks and the ten white socks. so to be certain of having two yellow socks, he needs to take two more.