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Coin tossing, probability and some logic, kinda


Swan Red

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On a different tack but kinda interesting none the less

 

There are a hundred dragons in an island. All of them have green eyes. There is a curse on the island where if a dragon realizes by itself that it has green eyes, it will turn into a sparrow at midnight. Because of this curse, none of the dragons are allowed to talk about eye color and none of them can look at their own reflection. One day a human comes along for a vacation to the island and he has a lot of fun with the dragons. While leaving at a farewell party where all the 100 dragons are present, he says something that the dragons already know "At least one of you have green eyes". The dragons know what the color "green" means and they are perfectly logical creatures.

 

This is a variant of an older puzzle and one that's pretty popular at the moment but it's still kinda cool, so what happens and when, if anything?

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14:20 approx

 

consider the same problem with two dragons, then three...

 

you're alright Gilps I just didn't think you'd be the one to call out not being believable

 

If there are 2 dragons then each dragon is aware that the other has green eyes. Therefore if the other dragon doesn't go piff-paff-poof at midnight, then each dragon becomes aware that it has green eyes. And piff-paff-poof, the next midnight both would go. Stretch it out and then on the 100th midnight they should all go piff-paff-poof.

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Nothing happens. As the riddle says; he's not telling the dragons anything they don't already know. They also already understand the colour of green and are perfectly logical. Given that they hadn't all gone 'poof' before the man said anything there is no reason why they won't continue the same as they already have done after his clue.

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Nothing happens. As the riddle says; he's not telling the dragons anything they don't already know. They also already understand the colour of green and are perfectly logical. Given that they hadn't all gone 'poof' before the man said anything there is no reason why they won't continue the same as they already have done after his clue.

 

Think this is the key bit, he is actually telling them new information. Trying to figure out how to prove this...irritating

 

Works with 2 dragons - both know at least one of them has green eyes, so if either didn't the other would know they actually did, so would go piff-paff-poof

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Think this is the key bit, he is actually telling them new information. Trying to figure out how to prove this...irritating

 

Works with 2 dragons - both know at least one of them has green eyes, so if either didn't the other would know they actually did, so would go piff-paff-poof

 

They all have green eyes. They can see that the other has green eyes. It doesn't help them to work out if they have.

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They all have green eyes. They can see that the other has green eyes. It doesn't help them to work out if they have.

 

Both dragons know that at least one of them has green eyes and can see the other one does.

 

So if Dragon 1 hasn't got green eyes he knows Dragon 2 will know that they must have. When Dragon 2 doesn't go PPP this confirms to Dragon 1 that he must have green eyes. So if there was only dragons they'd both go PPP together

 

I think

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If all the dragons have green eyes and know what green eyes means, then (assuming they can all see out of their green eyes) each 1 of the dragons knows the other 99 have green eyes, so the human saying 'at least one of you has green eyes' adds nothing to the mix, so they are as they were.

 

Unless they decided to eat him for being a c*nt.

 

 

 

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Then the human saying anything is irrelevant as they should have come to the same realisation in the first place.

 

Aye.

 

Crap riddle / puzzle. I guess the only inference could be that he doesn't say " at least one of you doesn't have green eyes " but that's stretching it.

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It definitely works when there's just 2 dragons, I'm not explaining it very well...

 

Pretty sure it works for any number, so that they'd all go PPP on day 100, or 101. I don't 'kin know....

 

so why haven't they already ?

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