[ Dirichlet's Principle (continued).]

In a bag, there are balls of two different colors: black and white. What is the smallest number of balls that need to be taken out of the bag blindly so that among them there are definitely two balls of the same color?

#
We need to draw three balls in total, so the balls are the "rabbits," and the colors are the "cages." Since there are fewer cages than rabbits, by the Pigeonhole Principle, there will be a cage with at least two rabbits. That is, two balls of the same color. It is easy to notice that by drawing two balls, we might get balls of different colors.

## Answer

3 balls.