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Miscellaneous thoughts and ramblings
Monday, May 02, 2005
 
Boolean Underpants
Those who don't like logic puzzles should read no further.

I was digging through archives of an old hard drive from an office I worked in a few years ago, and I found this puzzle I created.

(Yes, I sometimes make up logic puzzles. That's perfectly normal. Stop laughing.)

For those who enjoy this kind of thing it will be a pleasant waste of about 15 minutes. I'll put the solution as a comment in a couple of days. Come on, Godby. I know you can do it.

-------------------------------------

Larry, Moe and Curly are having a pleasant chat. One of the three always tells the truth. One of the three always lies. One of the three faithfully alternates true statements with false statements. A contiguous portion of their conversation is transcribed below.

Larry: I am wearing underwear.
Larry: Moe always lies.
Moe: Curly always lies.
Curly: Larry always lies.
Moe: I am wearing underwear.
Larry: Curly alternates true statements with lies.
Moe: Larry alternates true statements with lies.
Curly: Moe alternates true statements with lies.
Curly: I am wearing underwear.

Please determine who is the truth-teller, who is the liar, and who alternates. Also, who is wearing underwear?
Comments:
Larry alternates and is wearing underwear, Moe tells the truth and Curly lies?
 
What are you, Doctor Bean? A member of -- or a candidate for --MENSA?

I mean really, creating logic puzzles? Sometimes I can't even understand, much less solve logic puzzles!
 
I agree with the rabbi's kid! But who has the time to do this! NO MORE PUZZLES! I should be folding clothes or other wifely duties. Svenmom
 
The Rabbi's kid: Welcome. I see your comments all the time on Psychotoddler.

Good try, but no cigar. If Larry alternates and is wearing underwear, then his first statement ("I am wearing underwear") is true, so his second would be false, and his third ("Curly alternates true statements with lies") would be true. But that conflicts with your guess that Curly lies.

Please try again!

Torontopearl: I am an unabashed giant geek, and hope not to lose too much blog readership because of it. Oven and I, since high school, have been puzzle fanatics, and creating them is as fun as solving them. (Stop laughing, I said.)

As for MENSA, I think I read somewhere on treppenwitz that David is a member, which from his great writing, makes sense. Oven was a member a long time ago, but found the meetings and the other members quite dreary. He said it was basically full of smart people who wanted to hang out with other people knowing nothing about them but that they were smart. A fairly sorry crowd, if I remember his assessment. Oven, correct me if I'm wrong.
 
Svenmom: We cross-posted. (1) we gotta get you a blogger account (2) sorry, no. See my response to TRKs. (3) Thanks for financing our vacation last week.
 
It seems the problem is not solvable. The person telling the truth obviously is wearing the underpants. Therefore the person who is alternating has to make two false statements,

1. that he is wearing underpants

2. that someone else is alternating

The only person who has those two statements in the appropriate alternating order is Larry. However, that would make Larry's second statement true, that Moe lies, and therefore Curly would be the truth teller. But that does not jive with the statements that Moe and Curly make, ie Curly saying that Larry is lying, etc.

Or maybe I am missing something obvious?
 
Larry always lies.
Curly always tells the truth.
Moe alternates between true and false statements.

F
F
F
T
T
F
F
T
T
 
Oh, and Curly is wearing underwear.
 
Dilbert: clarification: any number of them, or none of them, may be wearing underpants. That is, you must tell me for each one whether or not he is wearing underpants. I hope that helps.
 
ahh, so more than one can be wearing underwear? that makes it a different problem.
 
good puzzle. :-)
 
Does it matter at all that I'm not wearing any underpants?
 
Ralphie: only to your wife.
 
Answer: Larry lies and is not wearing underwear. Moe alternates true statements with lies and is wearing underwear. Curly tells the truth and is wearing underwear.

Hagrin basically got it, except that he missed that Moe is wearing underwear.

Welcome, Hagrin.

Good job, all.
 
Thanks.

I even had that 5th statement marked as true and for some reason forgot to actually type the words Moe is wearing underwear. Silly me.

And you can thank the "Next Blog" button up at the top for my accidentally finding your space on the Internet.
 
Only the habitual liar does not wear underwear. I guess if you go around lying about everything, it doesn't really matter, does it?

On the other hand, the truthteller wears underwear. This makes perfect sense since he cannot lie. He probably avoids gassy foods too.

I was in MENSA for less than a year. I think they (Mensans) are good folks, but I was hoping for brainy activities/conversations and my group was not really not into that. So I let it go. I got in, which was the cool thing.
 
Oven: Good to see you back. I missed you. What have you been doing? Working? Spending time with your family? Stop that! Come on! Get your head in the game!
 
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