2009-03-16, 12:06 AM
Switch your door.
You have a 1/3 chance of getting the Chinchilla. Not good odds. Since the host opens a door revealing a pineapple, you are down to choosing two doors. Now since your door has a 1/3 chance of getting the Chinchilla, and the host already eliminated one door, it stands that the only door left has the Chinchilla 2/3 of the time, since you know the door you picked has the Chinchilla only 1/3 of the time.
This problem has sparked a huge raging debate amongst probability mathe-wannabes.
You have a 1/3 chance of getting the Chinchilla. Not good odds. Since the host opens a door revealing a pineapple, you are down to choosing two doors. Now since your door has a 1/3 chance of getting the Chinchilla, and the host already eliminated one door, it stands that the only door left has the Chinchilla 2/3 of the time, since you know the door you picked has the Chinchilla only 1/3 of the time.
This problem has sparked a huge raging debate amongst probability mathe-wannabes.