[Trevor]

"Bill Graham" wrote in message
...
Suppose for the moment that there are two contestants. One picks door two,
and the other picks door one. Then the moderator opens door three and
shows everyone that there is a donkey behind that door. Now, will it make
any difference if the other two switch their initial picks or not? And, if
they do swap doors, with they both enjoy a 2/3 chance of winning?

It get's really silly now when both switch doors! :-) However neither gets
100% chance of winning and one still loses. They both can't win 66% of the
time however. The problem is that the host can now only open one door if he
is not to pick one already selected, and since his door now has a 1/3 chance
of winning (rather than none as in the original game where he must always
select one that has a goat) NO new information is provided if his is
actually a goat/donkey. Therfore both contestentants now have a 50% chance
of winning whether they switch or not.
This in fact seems far more logical and thus obvious IMO.

Trevor.