A box contains 13 white marbles and 15 black marbles. Outside of the box, you have 28 black marbles. Without looking, you reach into the box and pull out two marbles. If they're of different colors, you put the white one back in the box. If they're of the same color, then you take them both out and drop a black marble in the box.
You continue under these conditions until only one marble remains in the box. What color is the last marble?
no subject
Splendid. Ahem.
A box contains 13 white marbles and 15 black marbles. Outside of the box, you have 28 black marbles. Without looking, you reach into the box and pull out two marbles. If they're of different colors, you put the white one back in the box. If they're of the same color, then you take them both out and drop a black marble in the box.
You continue under these conditions until only one marble remains in the box. What color is the last marble?