Puzzles | Logic puzzles | Pair of Socks | Solution

Three.

Reasoning

There'll be a matching pair of socks after three tries because only two socks, of either color, are needed. Let's say the first sock drawn from the wardrobe is black. There are only two things that can now happen: If the next sock is black, there's now a matching pair of socks and you're done. If the next sock is white, there's now a white and a black sock. Now, no matter what the next sock drawn will make a pair. Whether a black sock or a white sock is drawn from the wardrobe, there'll be two socks of one color and one of the other color. Therefore, there'll always be a pair by the third sock drawn.