Evil King Berman and the Fair Maiden

Here's how Ray solved the puzzler.

First, fill the 9 ounce glass with water.

Next, pour the water in the 9 ounce glass into the 4 ounce glass, until it is full. This leaves 5 ounces in the 9 ounce glass.

Now empty the 4 ounce glass.

Now, fill the 4 ounce glass, using the remaining water from the 9 ounce glass. Once the 4 ounce glass is filled, you'll be left with just 1 ounce of water in the 9 ounce glass.

Empty the 4 ounce glass of water again.

Transfer the 1 ounce of water from the 9 ounce glass into the 4 ounce glass.

Fill the 9 ounce glass with water.

Pour water from the 9 ounce glass into the 4 ounce glass, until the 4 ounce glass is full. Guess what? Since the four ounce glass already has 1 ounce of water in it, it will only take an additional 3 ounces of water.

Guess how much that leaves in the 9 ounce glass? You got it--6 ounces.

Congratulations, you're finished!

[ Car Talk Puzzler ]