NetNews Usenet Archive 1992 #31/NN_1992_31.iso/spool/rec/puzzles/8083

Text File | 1992-12-22 | 1.8 KB | 45 lines

Newsgroups: rec.puzzles
Path: sparky!uunet!cs.utexas.edu!sdd.hp.com!hpscit.sc.hp.com!hplextra!hplntx!potamian
From: [e-mail] (Spyros Potamianos)
Subject: Killers & Pacifist (NEW VARIATION)
Sender: [e-mail] (HPL News Posting Service)
Message-ID: <[e-mail]>
Date: Mon, 21 Dec 1992 22:23:25 GMT
Organization: Hewlett-Packard
Lines: 34


First, let me state the original puzzle:

    You arrive in a village (or island, or whatever) inhabited by
    K killers and P pacifists. Every day two persons are selected at
    random. If both of them are pacifists nothing happens. If one is
    a killer and the other a pacifist then the killers kills the pacifist.
    If both are killers, then they kill each other. You can join the
    "game" as a pacifist or a killer. Which choice maximizes your chance
    of survival?

The answer is that it doesn't matter. If K is odd (NOTE: 'K' is the number
of killers *before* you join) you die anyway. If K is even you have a
1/(K+1) chance of survival (no matter what you decide to become)

Now the new variation: Everything remains the same, except for a slight
change in the algorithm for selecting the two persons:

    Randomly choose a killer. Then randomly select another person
    (killer or pacifist).

If you don't believe that that's different from the original problem try
K=2, P=0. If you become a killer your chance of survival is 1/3, but if
you become a pacifist it's 1/2

Spyros Potamianos
[e-mail]

:-) :-) :-) :-) :-) :-) :-) :-) :-) :-) :-) :-) :-) :-) :-) :-) :-) :-)

P.S. BTW, I encoded a message in this post, and it has a pretty good chance
of surviving a billion years (yes, USENET will still exist...)

:-) :-) :-) :-) :-) :-) :-) :-) :-) :-) :-) :-) :-) :-) :-) :-) :-) :-)