How many?, page-30

Not enough information has been given to solve this particular riddle.

The OP stated that you need a matching PAIR of socks, which immediately rules out different colours, and surely implies you need both a left and a right foot sock (if you don't have both it's only two socks and not a pair). I suppose people who are sufficiently fashion-unconscious to wear different coloured socks would probably even wear them on the wrong feet.