## Number of Marbles in a Bag Containing Black and White Marbles

**Problem**

If 2 marbles are removed at random from a bag containing black and white marbles, the chance that they are both white is 1/3. If 3 are removed at random, the chance that they all are white is 1/6. How many black marbles are there?

**Answer Key**

## Click here to show or hide the answer key

Number of black marbles = 4