09 Sep '05 02:45>
You have a bag with 50 balls in it. 25 of the balls are white, and 25 are black. You draw two balls from the bag at a time. You don't know what color the balls are until you have removed them from the bag. If you draw two white balls, or two black balls, you place a white ball in the bag. If the draw is two balls of different color, you place a black ball in the bag. What is the color of the last ball in the bag? If you start with n white balls, and n black balls, when is the last ball white, and when is the last ball black?