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#1 bonanova

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Posted 06 February 2008 - 04:41 PM

In the Land of Knights and Knaves [LKK], Knights told the truth,
and Knaves always lied. When the rare averitas flu virus infected
some of the inhabitants, their behavior was reversed: sick Knights
began to lie, and infected Knaves had to tell the truth!


Your job is to find out the ones who have been infected so they can
be given the costly AFV vaccine. You've just dealt with six of them,
and now a group of ten LKK citizens is brought to your
office, and they venture the following information:

Who are the sick ones? and who are the Knights?


01. Alan: Jack is lying, or he's a Knight; but not both.
02. Bervin: Jack is lying, or I am a Knave; but not both.
03. Clarence: Harry might be a Knave, but only if he is well. Harry is well.
04. David: Harry might be a Knave, but only if he is sick.
05. Evan: Alan might be a Knave, but only if he is well.
06. Bervin: Alan might be a Knave, but only if he is sick. Alan is sick.
07. Fred: If Harry is sick, then Jack is lying.
08. Fred: Alan is lying.
09. George: Fred is lying.
10. George: No fewer than 4 of us are lying.
11. Evan: No more than 4 of us are Knights.
12. Alan: I am a Knight.
13. Harry: I am a Knave.
14. Ingolf: None of our statements is a paradox.
15. Jack: If 2+2=5, then New York is a small city.

Edit #1: Numbering the statements, to make discussion easier.
Edit #2: Bervin and Clarence change their stories, slightly.
[thx to s54 and wb!]
------------------------

If you like this type of puzzle, here are some others, recently posted to this forum.

Knights and Knaves get the flu [bononova]
Honestants and Swindlecants: The Delegation [octopuppy]
Knights, Commoners & Knaves [roolstar]
Four Knight and Knave problems [bonanova]
knights and liars [2] [bonanova]
knights, knaves and liars [bonanova]
3 Princess Puzzle [O'Beckon]
The Barber of Honestants and Swindlecants [spoxjox]
The liar, the truth teller....and the random answerer [Martini]
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The greatest challenge to any thinker is stating the problem in a way that will allow a solution.
- Bertrand Russell

#2 schmod54

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Posted 06 February 2008 - 05:53 PM

Oh my goodness... the horror. I'll give it a try.
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#3 Writersblock

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Posted 06 February 2008 - 07:10 PM

I think this needs clarification. Here's why:

Spoiler for Circular reasoning.


See what I mean? :huh:
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#4 schmod54

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Posted 06 February 2008 - 07:10 PM

Maybe I'm doing something wrong... but I couldn't find a unique solution.

Spoiler for My attempt


Care to give me a clue? Thanks for a good puzzle bonanova!
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#5 schmod54

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Posted 06 February 2008 - 07:17 PM

I think this needs clarification. Here's why:

Spoiler for Circular reasoning.


See what I mean? :huh:

Spoiler for ifs in logic

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#6 Writersblock

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Posted 06 February 2008 - 07:20 PM

Ah wait.... I think I see a flaw in my logic with Harry's statement. More to come soon... :mellow:

(posted just before I read the above, which is the flaw I saw. Let me give it another shot.)
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#7 bonanova

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Posted 06 February 2008 - 07:26 PM

Spoiler for Clarifying If ... Then ... statements.

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The greatest challenge to any thinker is stating the problem in a way that will allow a solution.
- Bertrand Russell

#8 bonanova

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Posted 06 February 2008 - 07:49 PM

Maybe I'm doing something wrong... but I couldn't find a unique solution.

Spoiler for My attempt
Care to give me a clue? Thanks for a good puzzle bonanova!

Spoiler for "#1: Where we agree and disagree so far ...
Spoiler for #2: Consider the statements in this order.

Off to the gym; will check back later.
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The greatest challenge to any thinker is stating the problem in a way that will allow a solution.
- Bertrand Russell

#9 Writersblock

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Posted 06 February 2008 - 07:53 PM

Couldn't get it either. This is as close as I came:

Spoiler for Details

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#10 bonanova

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Posted 06 February 2008 - 08:08 PM

Couldn't get it either. This is as close as I came:

Spoiler for Details

Spoiler for Are you sure about this?

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The greatest challenge to any thinker is stating the problem in a way that will allow a solution.
- Bertrand Russell




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