🚀 go-pugleaf

In article <1i7cb6INNe0@mirror.digex.com>, adric@access.digex.com (William Johnson) writes:
>Damn.  Someone help, please.  I know people are sick of this one, but....
>
>I see two lines of reasoning, and the one I intuitively feel is correct
>is not the one that logically seems correct.
>
>Reasoning one:  Once Monty shows you a door, the remaining two are one right
>	and one wrong, making the choice 50/50.
>Reasoning two:  Once you pick, you have a 2/3 chance of being wrong, and so
>	if one of the two wrong answers is shown, switching give you a 2/3
>	chance of being RIGHT.

I have not seen the show.  I assume Monty shows a wrong door whether
you have picked the right door or not.  Here are all cases with equal
chance:
		Door
	1	2	3
	R	W	W
	W	R	W
	W	W	R

Say you pick door 1, then Monty shows you a wrong door.  If you stay,
you got the Right in case 1, but Wrong for case 2 and 3.  If you switch,
you got the Right door in case 2 and 3, but wrong for case 1.  This is
the same if you start out with door 2 or 3.  Therefore, switching give
you a 2/3 chance.

he