Originally Posted by

**Dufus** There are 113 marbles in a jar. Five of them are red, the rest are blue.

There's a one in three chance you'll be selected to play the game.

If you are, then blindfolded, you shake the jar and draw one marble completely at random.

If it's blue, you keep it and the game is over.

If it's red, there's an [x/y] chance I'll let you keep it, or a [1-(x/y)] chance I'll make you put it back. Whether you get to keep it or not, the game is over.

I want there to be a 5% probability of you drawing a red marble and keeping it. So what should x and y be?