PWN the SAT Q&A

If you want a ratio of 4 to 3, start by listing the possible ways that could happen:

4 to 3
8 to 6
12 to 9

…and that’s it (since we’re only starting with 12 marbles of each color). From there, it should be obvious how few marbles need to be removed to create a 4:3 ratio. Just take away 3, and you’ve got 12 and 9.