jhsegal
From: jhsegal@wiscon.weizmann.ac.il (Livy)
Newsgroups: rec.puzzles
Subject: Re: meta-puzzles
Date: 5 Oct 92 18:54:15 GMT
Organization: Weizmann Institute of Science, Computation Center

In article <BvnL1u.pC@math.uwaterloo.ca> tjdonald@neumann.uwaterloo.ca () writes:
>Here are a couple of puzzles based on the sort of meta-logic problems
>Raymond Smullyan has written about in a few of his books. Are there any
>other sources for meta-problems? Smullyan's books are the only places I've
>ever come across any...
>
>
>1. On the island of knights and knaves, knights always tell the truth and
>   knaves always lie; and any person on the island is either a knight or a
>   a knave. It seems that a native of the island named Bob was suffering from
>   a particularly rare form of amnesia. It's a fact that Bob owned a total
>   of ten pets, all cats and dogs. It is also a fact he had more cats than
>   dogs. Luckily for Bob, his confusion was cleared up when his friend his
>   friend Marie came by and said "Either you have nine cats and one dog, or
>   you have an even number of both pets." Since Bob knew Marie's type (ie.
>   whether she was a knight or a knave), he figured out how many pets he
>   had right away. So the question is: How many cats does Bob own?

7 cats and 3 dogs
and Marie was a knave (liar)>
>
>2. There are two doors, 1 and 2, and only one leads to the grand prize (a
>   dump truck full of twinkies). You possess two keys, gold and silver, and
>   only one opens the door that leads to the twinkies. Here are three
>   statements:
>
>     i. The silver key opens the door that leads to the twinkies.
>    ii. The gold key opens door 2.
>   iii. Door 1 leads to the twinkies.
>
>   Unfortunately, you don't know which of these statements are true and
>   which are false.
>
>   I told Dr. Rocket everything I've just told you. Unable to solve the
>   problem, Dr. Rocket asked me if there more true statements than false
>   statements among i-iii. After I responded (with the correct answer, of
>   course!), the good doctor was still unable to solve the problem. As
>   another hint, I told Dr. Rocket the truth value of one of the statements
>   (although I forget which one) - and almost before I finished speaking
>   the doctor blurted out the correct solution. Can you determine: 1) Which
>   door leads to the twinkies, and 2) Which key opens that door?
>
hmm..Somethink stinks here...I thought about it for a while,and I arrived to
something impossible(all of them must be true,in some situation),so I think
the writer of this one didn't thought enough  about it.Anyway...I am not sure
I am right(in fact I think I am not!),but I don't feel like thinking about it
more.This is my guess: Silver opens door 2 who leads to the twinkies.

Not true,huh?
I knew!

 ---------------This Was Another L I V Y ' S  Production----------------------

  __     __  __    ___ __     _     ___   __
    |      |   \     /   |     \       \    | VM/CMS:
    |      |    \   /    |    _ \       \   | JHSEGALL @ Weizmann.weizmann.ac.il
    |___   |       /     |    _  \    |  \  | UNIX:
        |  |      /      |   /    \   |     |  JHSEGAL  @ Wiscon.weizmann.ac.il
Newsgroups: rec.puzzles