Some of you might remember the Sock Drawer Puzzle that we published over two years ago. Well here is another one.
Back then we had a mixture of black and white socks, and we still do. We have 17 pairs of black socks and 15 pairs of white socks, all in a drawer and still unpaired. We have also added a single pair of red socks that were a Christmas present - we would not normally have anything but black or white, but we can't get rid of a present.
The other day the lights were off and we could not see the sock drawer contents. How many socks did we need to take from the drawer to ensure that we had at least one matching pair?
In spite of the large numbers of black and white socks we needed to take just four socks from the drawer. There are three colours of socks, black, white and red, and taking three socks could result in one of each. Taking one further sock would then ensure a matching pair.