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From: jeff@hpcnoe.UUCP
Newsgroups: net.games.board
Subject: Re: Dice "Odds"
Message-ID: <37800027@hpcnoe.UUCP>
Date: Sat, 14-Dec-85 20:59:00 EST
Article-I.D.: hpcnoe.37800027
Posted: Sat Dec 14 20:59:00 1985
Date-Received: Tue, 14-Jan-86 07:48:12 EST
References: <309@tekigm2.UUCP>
Organization: 14 Dec 85 18:59:00 MST
Lines: 28

> Given that you use two dice in a game and that you are trying to figure 
> the odds of getting a particular combination:  do you use the combinations
> or the permutations to determine the odds?
> 
> 	    Permutations                        Combinations
>         Number        Ways                   Number       Ways
> 	  2             1                      2            1
> 	  3             2                      3            1
> 	  4             3                      4            2
> 	  5             4                      5            2
> 	  6             5                      6            3
> 	  7             6                      7            3
> 	  8             5                      8            3
> 	  9             4                      9            2
> 	  10            3                      10           2
> 	  11            2                      11           1
> 	  12            1                      12           1
>                        ---                                 ---
> 		       36                                  21
> 

Actually, in the strict mathmatical sense, this is neither a "permutations"
problem nor a "combinations" problem--factorials are not involved.  The
correct answer is the left column e.g.  there is two ways of throwing a
three (1 2) and (2 1), the two are equally likely because the dice have
no knowledge of what the other has thrown.

-- Jeff Wu