The Singapore Logic Puzzle

[Teremia]

Frelga, just a clarification: is the sum really (x + 1), not (x + y)?

[Frelga]

Oh, oops. You are correct (as always), it's X+Y. I fixed the puzzle post.

[tinwë]

I more or less ignored this (the Singapore logic puzzle) when it first started making the rounds (I recall someone, it may have been Lidless, posting it on their Facebook page and my response was "can we go back to talking about the color of the dress, I'm good at that"), but I showed it to one of my co-workers today and she got sucked into it and after she couldn't wrap her head around it I tried to explain, since I had by that point read the various explanations. Mind you, I didn't really understand it even then, but after analyzing the solution I finally thought I had it.

And I have now come to the conclusion there is a flaw in the puzzle. Someone smarter then me please help me out here.

Hidden text.

ok, so I get the first statement by Albert. There is only one way that Bernard could know the answer with no additional information - if it was a unique number. There are only two uniques numbers - 18 & 19. Those numbers only occur in May and June, so the only way Alturd could know that Bernads does not know the the month is if the month is not May or June. Once Bernardo knows that, he automatically knows the answer. That much is clear, because once you have eliminated May and June you are back to where you were at the beginning - whatever is a unique number must be the answer. There are three unique numbers left - 15, 16, & 17. At this point there is no doubt that Bernoulli knows the answer. He must, because he knows the date. It has to be one of those three. This is where it gets tricky though. We know from the wording of the second statement that Alturo knows the answer, and we assume that Bergundy knows the answer because he knows the month, but what is to stop the answer from being either August 15 or August 17? I contend that it just as easily could have been either of those, based on the information given in the puzzle. The last statement made by Burgonini can only be true if we just assume that he was told the month was July. The correct answer could just as easily be August 16 or 17, and Burbullyboy could just be full of shit because he thinks he has a shot at scoring a date with the babe Cheryl to the prom. Dumbass.

[tinwë]

Arrrrgggghhhh! I can’t believe I spent sooooo much time agonizing over this. Thanks Ax.

I think I understand it now:

Hidden text.

May 15 May 16 May 19
June 17 June 18
July 14 July 16
August 14 August 15 August 17

The solution depends on one thing - no one can ever know the answer unless it is a unique date. So, right from the start Albert (who knows the month) cannot know the answer because there is no unique month. Bernard, on the other hand could know the answer if it is either 18 or 19, since those are unique dates. The only way Albert can say that Bernard doesn’t know is if the month is not May or June, so after the first statement the puzzle has been reduced to this:

July 14 July 16
August 14 August 15 August 17

There are still no unique months, but there are now three new unique dates: 15, 16 & 17. If Bernard says he knows the date, it must be one of those. In fact the only way he could not know the date at this point is if was the 14th. So 14 is out and the puzzle is now down to this:

July 16
August 15 August 17

For the first time there is a unique month, July, so when Albert says he knows, that can only be true if the month is July. Leaving:

July 16

So, there. And having at last gained his confidence, Albert finally makes the decision he has dreamed of his entire life, and transitions into Alberta. Cheryl dumps Darla and takes Alberta to the prom and they live happily ever after.

The end.

I'm not even looking at the hat puzzle.

[Inanna]

Giggle. Hugs tinwë. You got it.



---------------
Please bear with my typos & grammar mistakes. Sent from my iPhone - Palantirs make mistakes too.

[Dave_LF]

Three logicians walk into a bar. "Y'all want a drink?" asks the bartender. "I don't know," says the first logician. "I don't know," says the second logician. "Yes!" says the third.

[Inanna]

What?


---------------
Please bear with my typos & grammar mistakes. Sent from my iPhone - Palantirs make mistakes too.

[Primula Baggins]

Well, if the first two don't know, the third must know (if one postulates that one of the three must know). It makes perfect sense. <pounds cane on porch> <orders the two drinks the other logicians were too weak to admit they wanted>

<and they'll be paying for them, of course>

[Dave_LF]

To correctly answer the question "do you all want drinks?" with a yes, you need to know that every single member of the group wants one. To correctly answer it with a no, you only need to know that at least one member (e.g. yourself) does not want one.

[yovargas]

So is the joke that the 3rd logician is pushing drinks on the other two?

[Jude]

If the first responder didn't want one, he'd know the answer was "no". So he said he didn't know. Which made it obvious that he wanted one.
Ditto for the second responder.
So the third responder knew that the other two wanted one, and he knew that he wanted one, so he knew they all wanted one.

[yovargas]

Ahhh, of course......

[Frelga]

Isn't y'all singular?

[Inanna]

So it was a logic game. I was confused because I was like - what was the Q? Not that I worked out any of it...

Giggle, prim & Frelga.


---------------
Please bear with my typos & grammar mistakes. Sent from my iPhone - Palantirs make mistakes too.

[Primula Baggins]

Yes, Frelga, and "all y'all" is the plural.

Or perhaps I'm missing a nuance here? I wish Anthy would show up and correct me!

[Alatar]

Or they could have been Irish, in which case nobody actually knew whether they wanted a drink until it had been offered at least three times.

I should write an "Irish Logic Puzzle". Would be much more fun.

[Primula Baggins]

Do keep in mind that the size limit on posts here is 60,000 characters.

[Jude]

How many of those characters are allowed to have an arc?