Kerry has a game that uses 20 tiles that are the same shape and size. 4 of the tiles are rectangles. 8 of the tiles are trapezoids. The remainder of the tiles are hexagons. Kerry chooses one hexagon tile from the bag and then gives the bag to her friend Pam without putting the tile back. If Pam takes one tile from the bag without looking, what is the probability that the tile she chooses will be a trapezoid?