Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Posting-Version: version B 2.10 5/3/83; site security.UUCP
Path: utzoo!linus!security!wdr
From: wdr@security.UUCP (William D Ricker)
Newsgroups: net.math
Subject: Re: Solution to second coins problem
Message-ID: <441@security.UUCP>
Date: Wed, 24-Aug-83 14:27:58 EDT
Article-I.D.: security.441
Posted: Wed Aug 24 14:27:58 1983
Date-Received: Wed, 24-Aug-83 19:05:20 EDT
References: <2124@umcp-cs.UUCP>
Organization: MITRE Corp., Bedford MA
Lines: 23

Sorry, Chris, your 75% is wrong.

What you failed to notice is that though case 1 and case 2 are in
general equlally likely, there are not equally likely in the realm of
discussion.

Case 1 and Case 2, Silver down and Silver Up, are equally likely only
before any drawers are opened.  They are equally likely set-ups.
However, Two-Thirds of Case One and One-Third of Case two are excluded
from the universe of consideration:  the subcases of Silver showing in
the first drawer, a bottom drawer, opened.

Thus in the realm of discussion, a bottom drawer showing gold, Case 2
is TWICE as likely.

I hope this helps clear things up for those of you who had questions
about choosing the state-space to count.

             Bill Ricker 
       (617)271-3725 MS k203, The MITRE Corporation, Bedford, MA, 01730
       wdr@security.UUCP					    (Internet)
      {allegra,genrad,ihnp4,utzoo,philabs,uw-beaver}!linus!security!wdr (UUCP)
       wdr@mitre-bedford						(ARPA)