In complete darkness, how many gloves must she take from the drawer in order to be sure to get a pair that match?
Think carefully!
Say the first she takes is Brown.
Say the second is Black.
Now, the third can be either Brown or Black, and either colour will make a pair.
(Say it is Brown, then it shall make a pair with the first socks.)
(Say it is Black then it shall make a pair with the second socks.)