Math
posted by Bianca on .
A drawer contains 22 black socks, 22 white socks, 22 blue socks, and 22 brown socks. If the light is off and Matt reaches into the drawer to get his socks, what is the minimum number of socks he must pull out in order to be sure that he has a matching pair?
He must pull out a minimum of ???? socks.

If there are four colours of socks (as in this case).
If I pull out 5 socks, can you tell me if it is possible NOT to have a pair of the same colour?