There are $$4$$ black socks and $$4$$ red socks in a drawer. Cindy wants to take out a pair of socks but the light in the room goes off. How many socks must she get from the drawer to make sure there is at least one pair of the same colour? 
Overseas Competition->Knowledge Point->Counting Modules->Permutations and Combinations->Combinations Overseas Competition->Knowledge Point->Combinatorics->Pigeonhole Principle->Worst Case in Pigeonhole Principle Problems