A box contains 24 tiles. Each tile has certain properties:
Each tile is made of wood or plastic.
Each tile is red, yellow, or blue.
Each tile is a triangle, square, pentagon, or circle.
There is exactly one tile for each combination of properties. For example, there is one red circle that is made of wood.
Steve chooses one tile, and Ellen chooses a different tile.
What is the probability that both tiles are red?
In this problem, in total there are 2 x 3 x 4 = 24 possibilities of tiles. Out of those 2 x 4 = 8 are red. So the chance Steven gets a red tile in 8/24 or 1/3. But now that Steven took out a tile there are only 23 tiles left. And because seteven took one of the 8 red tiles, there are now only 7 red tiles. So 1/3 x 7/23 = 7/69