2015 marbles in a box, 3 colors at start, one color in the end
Source: INAMO Shortlist 2015 C3
May 14, 2019
ColoringColor problemcombinatorics
Problem Statement
We have marbles in a box, where each marble has one color from red, green or blue.
At each step, we are allowed to take different colored marbles, then replace it with marbles with the third color. For example, we take one blue marble and one green marble, and we fill with red marbles.
Prove that we can always do a series of steps so that all marbles in the box have the same color.