Also solved on CAR talk with a different number of prisoners. Note that
Click and Clack state that a 6th grader can solve the problem without
deep math or statistics.
http://cartalk.cars.com/Radio/Puzzler/Transcripts/200307/answer.html
Roy Robertson
"Opinions expressed are mine and not those of Rohm and Haas Company".
"David Homiak" <dhomiak@xcaliber.com>
Sent by: s-news-owner@lists.biostat.wustl.edu
12/18/2003 01:34 PM
To: "Arthur Nadas" <nadas@env.med.nyu.edu>,
<s-news@lists.biostat.wustl.edu>
cc:
bcc:
Subject: Re: [S] Early release?
This is actually a deterministic logic puzzle. Perhaps your friend has
visited the IBM web site where a variation was posted in July, 2002, at
http://domino.research.ibm.com/Comm/wwwr_ponder.nsf/challenges/July2002.html;
the solution is also given there.
Dave Homiak
dhomiak@xcaliber.com
-----Original Message-----
From: Arthur Nadas [mailto:nadas@env.med.nyu.edu]
Sent: Thursday, December 18, 2003 12:10 PM
To: s-news@lists.biostat.wustl.edu
Subject: [S] Early release?
Dear S-Plus Colleagues,
A very sharp mathematician friend sent me this puzzle from prison.
Although not explicit, it has, in my opinion, fairly deep statistical and
probabilistic content. I thought some of you might enjoy thinking about
it. Please send me your thoughts at (nadas@env.med.nyu.edu) and I will
transmit them to my friend and summarize putative solutions
for this list. Here is the puzzle:
************************************************
Early release?
In a cost cutting measure brought on by the budget crisis, the warden at
the prison brought together four lifers and made them the following offer:
"Intermittently and at my whim I will begin picking you, one at a time, to
come to this room and stand before those two unconnected light switches.
You may observe the positions of the switches and then you must switch one
of them. At this point you also have the option of telling me: 'All four
of us, have by now, visited this room without the others.' If this claim
is correct then all of you will be immediately released. If the claim is
wrong, you will all be executed.
I may pick the same person several times in a row, but I will eventually
pick every one of you. Once I have picked you, I will eventually pick you
again and again, ad infinitum, as long as no one has made the claim. You
each will be kept in total isolation except for these visits. I will give
you time here together to plan your strategy, and when you have decided
and leave here, I may change the way the switches are now, but after that
only you guys will be allowed to touch them. No tricks."
What should they do?
Arthur Nádas
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