Hi Al,

>1. There are exactly 2 doors remaining.

That's the point. 2 doors are remaining which means, there are more doors involved. They point is, you can't simply remove one door from this 3-door game, because statitistically, you don't know which one. If you remove one there's 1/3 probability, that you remove the door with the boat. This 1/3 is exactly, what must be added to the 50% probability of your 2-door game, ie. 0.5*1.33 = 0.66, the probability that changing gives you the right door.

Christof