Here is the answer:
http://cartalk.cars.com/Radio/Puzzler/Transcripts/200307/answer.html
__________________________________________________________
James Holtman "What is the problem you are trying to solve?"
Executive Consultant -- Office of Technology, Convergys
james.holtman@convergys.com
+1 (513) 723-2929
nadas@env.med.nyu.edu
(Arthur Nadas) To:
s-news@lists.biostat.wustl.edu
Sent by: cc:
s-news-owner@lists.biosta Subject: [S] Early
release?
t.wustl.edu
12/18/2003 13:09
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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