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Halcyon Daze

A riddle given to 14yo Maths Students

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In case you haven't seen it yet

This riddle showed up in a maths exam for 14 year olds.

Can you do it? I did :)

No peeking at the answer!

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Edited by Halcyon Daze

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.

.

I SAID NO PEEKING!!!!!!!!!!!

.

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YOU'RE A WINNER BABY!!!

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Edited by Halcyon Daze
  • Like 1

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June 18

Why?

Only two June dates out of all other possible months
Only one 18 for the day out of all the other possible days
Any other day/month combo wouldnt be conclusive because others couldnt be ruled out.

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WTF That can't be right, can it?!?!

LOL, keep guessing Ace!

Edited by Halcyon Daze

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From this riddle I can work out that Cheryl is a bitch.

  • Like 14

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Maths exam for 14 year olds in Korea maybe.

I am guessing the trick is to, since only one knows the day and one knows the month, figure out who knows which and deduct from that.

Either way, she won't have them as friends for long...

Edited by archaeologistintraining
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Nice riddle!

Choices:

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

Albert knows that Bernard doesn't know. This means it can't be May 19 or June 18, as if Bernard knew these days (18 or 19), he would have already figured it out.

May / 15, 16, 19
June / 17, 18
July / 14, 16
August / 14, 15, 17
Bernard doesn't know to start with, but now he knows Albert definitively thinks he couldn't have known beforehand. So, he knows the month can't be May or June, as only July or August have all non-unique days.
May / 15, 16, 19
June / 17, 18
July / 14, 16
August / 14, 15, 17
For Bernhard to now know the answer, given he was only told a day, it must have been either July 16, or August 15 or 17, because if he was told 14, he couldn't be sure between July 14 and August 14.
May / 15, 16, 19
June / 17, 18
July / 14, 16
August / 14, 15, 17
Now that Albert knows Bernard has the answer, he can figure that it must have been July 16, because otherwise Bernard couldn't have been sure, as there are two choices left in August.
These kind of puzzles are called induction puzzles or common knowledge logic puzzles. Another tricky one is the Muddy Children problem.
It's crazy to think that there are many 'levels' of knowledge...
  • I know the answer. July 16.
  • Now I know that you know I know the answer.
  • Now I know that you know I know you know I know the answer.
  • Now I know that you know I know you know I know you know I know the answer.
  • Now I know that... etc., ad infinitum... whoa dude.
mind-blown-2.gif
Edited by antonsyd

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Yep, it's quite simple when you realise you can rule out May and June right from the second half of the opening sentence. ie "I know that Bernard does not know too."

That leaves just July and August.

Bernard says "well now I know" because he knows it's 16 (of either May or July and it can't be May)

And Albert now knows for sure because He already knows it's July, and because Bernard could only know it if it was July 16 (If it was 14 then Bernard would not have been able to know).

Simple :)

Edited by Halcyon Daze
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I want those 2 minutes of my life I spent reading this back. So I guess the answer is 2. :blink::scratchhead:

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Albert and Bernard replied in unison 'Fuck off then Cheryl'

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Cheryl masturbates by counting backwards from 13 minutes. She climaxes at precisely 0 seconds.

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the f did i just raed

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I hate it when u have to do these kinda tests before u get an interview for some jobs. My brain instantly puts it in the fuk this bs pile :( my brain is just lazy I guess I couldn't even read through the question :(

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I honestly couldn't care enough to work this out without some kind of reward whether it be material or arbitrary.

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i pledge 1 arbitrary reward ^

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