some colored balls (at least 3 different colors) and at least 3 boxes ...
Source: Mexican Mathematical Olympiad 2001 OMM P2
July 30, 2018
combinatoricsballsColoring
Problem Statement
Given some colored balls (at least three different colors) and at least three boxes. The balls are put into the boxes so that no box is empty and we cannot find three balls of different colors which are in three different boxes. Show that there is a box such that all the balls in all the other boxes have the same color.