Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Posting-Version: version B 2.10 5/3/83; site teklabs.UUCP
Path: utzoo!linus!decvax!tektronix!tekchips!teklabs!keithe
From: keithe@teklabs.UUCP
Newsgroups: net.math
Subject: six coins in the cabinets
Message-ID: <2354@teklabs.UUCP>
Date: Fri, 19-Aug-83 12:56:27 EDT
Article-I.D.: teklabs.2354
Posted: Fri Aug 19 12:56:27 1983
Date-Received: Sat, 20-Aug-83 08:43:34 EDT
Organization: Tektronix, Beaverton OR
Lines: 45

Let me expand on Ken Turkowski's explanation:

After you select a gold coin, you have the following possible
systems:

Possibility 1:
    G1 in hand
     -------------          -------------
    |             |        |             |
    |   empty     |        |     G3      |
    |             |        |             |
     -------------          -------------
    |             |        |             |
    |     G2      |        |     S3      |
    |             |        |             |
     -------------          -------------


Possibility 2:
    G2 in hand
     -------------          -------------
    |             |        |             |
    |     G1      |        |     G3      |
    |             |        |             |
     -------------          -------------
    |             |        |             |
    |   empty     |        |     S3      |
    |             |        |             |
     -------------          -------------


Possibility 3:
    G3 in hand
     -------------          -------------
    |             |        |             |
    |    G1       |        |    empty    |
    |             |        |             |
     -------------          -------------
    |             |        |             |
    |    G2       |        |     S3      |
    |             |        |             |
     -------------          -------------

Now you can see that there are 2 out of 3 chances of
selecting a gold coin from the other drawer.