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Message from discussion 1/2<->1/3
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Joe Keane  
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 More options Jun 1 1999, 3:00 am
Newsgroups: rec.puzzles
From: Joe Keane <j...@jgk.org>
Date: 1999/06/01
Subject: 1/2<->1/3
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You visit Dr. Evil's lab for an experiment.  The following protocol is
explained to you and you remember it at all times.

On Sunday you're put to sleep with drugs.  That night, Geddy Lee flips a
fair coin and rolls a fair die.

On Monday and Tuesday, according to the conditions below, you may be
woken up by Nurse Chapel.  After this, Will Smith pulls out his penlight
and pushes the history eraser button, and you forget being woken up.

On Monday, you're woken up if and only if the die shows 1.

On Tuesday, you're woken up if and only if: the coin shows heads and the
die shows 1; or, the coin shows tails and the die shows 2.

On Wednesday, Dr. Franklin shoots you up and sends you on your way.

...

You're woken up by Nurse Chapel.

What's the chance the coin is heads?

--
Joe Keane, amateur mathematician


 
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