Friday night Brain teaser

[woolmilk]

"1. If only one person on the island has blue eyes then he can look around and see 99 pairs of brown eyes. Therefore, he knows that he must be the one with the blue eyes and kills himself that night."

I think this is _not_ a proof of beeing blue-eyed.
If you dont see any blue-eyed people, then how it comes "you" are blue-eyed ? Since mr.superior did not give any numbers, theres no proof that a single blue eyed really exists. "You" would live happy as brown-eyed man among brown-eyed man until the invention of speech.

 

[calbear2000]

<< "1. If only one person on the island has blue eyes then he can look around and see 99 pairs of brown eyes. Therefore, he knows that he must be the one with the blue eyes and kills himself that night."

I think this is _not_ a proof of beeing blue-eyed.
If you dont see any blue-eyed people, then how it comes "you" are blue-eyed ? Since mr.superior did not give any numbers, theres no proof that a single blue eyed really exists. "You" would live happy as brown-eyed man among brown-eyed man until the invention of speech. >>




This scenario is impossible since:
> 10 of them
> have blue eyes and 90 of
> them have brown eyes.

 

[notfred]

<< "1. If only one person on the island has blue eyes then he can look around and see 99 pairs of brown eyes. Therefore, he knows that he must be the one with the blue eyes and kills himself that night."

I think this is _not_ a proof of beeing blue-eyed.
If you dont see any blue-eyed people, then how it comes "you" are blue-eyed ? Since mr.superior did not give any numbers, theres no proof that a single blue eyed really exists. "You" would live happy as brown-eyed man among brown-eyed man until the invention of speech. >>



I have to agree with this.

 

[woolmilk]

"This scenario is impossible since:
> 10 of them
> have blue eyes and 90 of
> them have brown eyes. "

No, this scenario can happen when most of the blue-eyeds are dead.
I think, there is no proof in this scenario.

 

[calbear2000]

<< "This scenario is impossible since:
> 10 of them
> have blue eyes and 90 of
> them have brown eyes. "

No, this scenario can happen when most of the blue-eyeds are dead.
I think, there is no proof in this scenario. >>




You're basing your argument on the possibilty that there are no blue-eyed people since the ultimate being didn't guarantee it. But I stated in my original post that there are 10 blue-eyes.

 

[shadowscavenger]

<< 2. If two people have blue eyes, then each can look around and see the other person's blue eyes along with the remaining 98 pairs of brown eyes. They both go to sleep that night thinking that the person they see with blue eyes will kill himself like in situation 1 above. However, when both wake up the next morning and see that the other person with blue eyes didn't kill himself, then they know that they themselves must have blue eyes also and therefore both blue-eyed people kill themselves on the second night. >>



what if the people wernt smart enuf to think about this, then they would just wonder why each other didnt kill themselves, and still thinking to themselves they both had brown eyes? just cause someone with blue eyes didnt kill himself doesnt mean you have to have blue eyes also, ;p

 

[calbear2000]

<<

<< 2. If two people have blue eyes, then each can look around and see the other person's blue eyes along with the remaining 98 pairs of brown eyes. They both go to sleep that night thinking that the person they see with blue eyes will kill himself like in situation 1 above. However, when both wake up the next morning and see that the other person with blue eyes didn't kill himself, then they know that they themselves must have blue eyes also and therefore both blue-eyed people kill themselves on the second night. >>



what if the people wernt smart enuf to think about this, then they would just wonder why each other didnt kill themselves, and still thinking to themselves they both had brown eyes? just cause someone with blue eyes didnt kill himself doesnt mean you have to have blue eyes also, ;p >>




You have to assume the fear of dying and the unwavering need to obey the superior being made them use some brain power to come up with their conclusions

 

[woolmilk]

"You're basing your argument on the possibilty that there are no blue-eyed people since the ultimate being didn't guarantee it. But I stated in my original post that there are 10 blue-eyes."

Ok, but if i look around and see 9 blue eyes and 90 brown eyes, there is no proof that "Me" is has blue eyes, because i dont now the number. And if these 9 blue eyes are all alive after 9 days, theres still no proof. And if i see 10 blue eyes and 89 brown eyes, theres also no proof that "Me" has blue eyes or brown eyes.
The number of existing blues and browns that i see dont help "me" determining "myself".

 

[calbear2000]

<< "You're basing your argument on the possibilty that there are no blue-eyed people since the ultimate being didn't guarantee it. But I stated in my original post that there are 10 blue-eyes."

Ok, but if i look around and see 9 blue eyes and 90 brown eyes, there is no proof that "Me" is has blue eyes, because i dont now the number. And if these 9 blue eyes are all alive after 9 days, theres still no proof. And if i see 10 blue eyes and 89 brown eyes, theres also no proof that "Me" has blue eyes or brown eyes.
The number of existing blues and browns that i see dont help "me" determining "myself". >>



I don't think you understand the solution.

If you see 9 blues and 90 browns, and on the 9th day, they're not all dead. That proves you are blue eyes.

Take the simple example of 2 blues and 98 browns... you and I are blue and everyone else is brown. We see each other and I think you're the only blue and I wait for you to commit suicide on the 1st night. You're thinking the same thing. We both wait and nothing happens. That means 1 other person is definitely blue.

 

[woolmilk]

"Take the simple example of 2 blues and 98 browns... you and I are blue and everyone else is brown. We see each other and I think you're the only blue and I wait for you to commit suicide on the 1st night. You're thinking the same thing. We both wait and nothing happens. That means 1 other person is definitely blue."

No. What would be if you see the only one with blue eyes ? He has no proof that he has blue eyes and would not commit suicide.

Just because superior says "if you recognize yourself as blueeyed you have to die" does not imply that any blueeyed must die unless there is a proof for the individual.

 

[calbear2000]

<< "Take the simple example of 2 blues and 98 browns... you and I are blue and everyone else is brown. We see each other and I think you're the only blue and I wait for you to commit suicide on the 1st night. You're thinking the same thing. We both wait and nothing happens. That means 1 other person is definitely blue."

No. What would be if you see the only one with blue eyes ? He has no proof that he has blue eyes and would not commit suicide.

Just because superior says "if you recognize yourself as blueeyed you have to die" does not imply that any blueeyed must die unless there is a proof for the individual. >>



Ok, I'll explain the base case one more time....

If you and I are blue eyes. I will count 1 blue and 98 brown. I do not know about myself yet. I assume I am brown, and I wait for you to commit suicide on the first night. You are thinking the same thing.

The first night passes, and no one commits suicide. That is my PROOF that there has to be 1 more person thats blue eyes, and that person is me.

I think I see the point you are bringing up though. I think your point is this:
If you committed suicide on the first night, then I know that you saw 99 brown eyes and realized that you are the only one. But you cannot arrive at that conclusion if the superior being didn't say there was at least 1 blue.

BUT, the initial condition was that there are 10 blues. So you would see > 1 blue. And thus, that negates your scenario.

 

[woolmilk]

Ok, now you say superior did not give a number but say "at least one" ! This is different from your first post.

And if superior says "at least one", and all you see is brown-eyed, then you have a problem.
But if you see plenty blue-eyed then the problem is solved, because there is at least one, and there is _no individual_ proof, that you have blue eyes.

 

[calbear2000]

<< Ok, now you say superior did not give a number but say "at least one" ! This is different from your first post.

And if superior says "at least one", and all you see is brown-eyed, then you have a problem.
But if you see plenty blue-eyed then the problem is solved, because there is at least one, and there is _no individual_ proof, that you have blue eyes. >>



Nice try... but I never changed what I said.

If you read and understood my last post, I was saying your point is correct if there was only 1 blue. Then he wouldn't have proof if superior hadn't made asserted any assumptions.

If you read on, I said "BUT, the initial condition was that there are 10 blues. So you would see > 1 blue. And thus, that negates your scenario. "

Which is the point you've been missing.

I think you finally understand... congratulations.

 

[woolmilk]

If you read on, I said "BUT, the initial condition was that there are 10 blues. So you would see > 1 blue. And thus, that negates your scenario. "
Which is the point you've been missing.
I think you finally understand... congratulations.

Well, thanx - UHHH NO, wait...
As I posted before theres *no proof for the individual* and the numbers you can count doesnt matter (except when superior tells you a number or something like "at least").

 

[calbear2000]

Sigh.

You're not understanding the solution. Rather than try to explain it again, I'll give you the weekend to think about it and hopefully you'll realize you don't need the superior to tell you how many blues there are.

Good luck

 

[MisterNi]

I think my variation is a bit more precise. Here it is:

There's a monastery that houses monks that live on logic. these monks only care about logic and nothing else, so there're no mirrors in the monastery. The monks are also very absorbed in what they do so they never converse with each other or communicate in any way with one another (even if it means death).

The only time a monk sees another is during dinner at the dinner table. The head monk (who can speak but not be spoken to) notices that some of his under-monks have the fatal Green Forehead Disease (GFD). To this, the head monk states to the rest of his monks, "I notice that some of you have contracted GFD, if you find you have contracted GFD, please leave the monastery after dinner. After three days, all of the infected monks have left. How many monks have left?

Answer: Of course the answer is 3 monks.

Solution: If only one monk were infected with GFD, then he would not see any other monk with GFD and leave that night.

If two monks were infected, either of the infected monks would see one monk with GFD. He would then assume that monk to leave night. The next night when they meet for dinner, both monks would see the GFD monk return for dinner. This would cause both the infected monks to realize there must be another infected monk, and since there is no other monk with GFD, he would logically deduce that other GFD monk were himself. Both would leave that night

And so on for three.

Same poop, different day.

 

[Sir Fredrick]

This solution is inherently flawed, unless the people in this scenario know the numbers. For example, if all 100 of them know that there are 10 blue eyes among them, the solution is more plausible. If the people don't know the numbers, there is no way that they can look around and count and assume that they must be one color or the other. And if they know the numbers, they don't have to use your complex solution, they can just count the number of blue eyes, and if they come up one short, they know they're it.

 

[911paramedic]

I think they all kill themselves that very night. I will explain why:

If you have blue eyes, everybody that looks at you goes :Q

If you have brown eyes, everybody that looks at you goes

 

[MisterNi]

<< This solution is inherently flawed, unless the people in this scenario know the numbers. For example, if all 100 of them know that there are 10 blue eyes among them, the solution is more plausible. If the people don't know the numbers, there is no way that they can look around and count and assume that they must be one color or the other. And if they know the numbers, they don't have to use your complex solution, they can just count the number of blue eyes, and if they come up one short, they know they're it. >>


Try it with 2 blue eyes. If you can understand that, then next try 3 blue eyes. If you can understand that then try 4, 5, 6 etc. There's nothing flawed about the answer.

 

[911paramedic]

It will not work unless the "supreme being" tells them how many have blue eyes, why else would they need to know how to count.

If there were 10 on the island, 9 with brown, 1 with blue. The 9 would see the one with blue eyes and not kill themselves, the one with blue would only see brown, and would not kill himself. The next day, they would see the same thing, but the brown eyed peeps would still see one with blue eyes. The blue eyed dude would still see nothing but brown and think, ok, all brown, no problems.

This would continue forever, as they never knew how many had blue eyes. They need to know that one or more has blue eyes, or it will not work.

 

[MisterNi]

<< It will not work unless the "supreme being" tells them how many have blue eyes, why else would they need to know how to count.

If there were 10 on the island, 9 with brown, 1 with blue. The 9 would see the one with blue eyes and not kill themselves, the one with blue would only see brown, and would not kill himself. The next day, they would see the same thing, but the brown eyed peeps would still see one with blue eyes. The blue eyed dude would still see nothing but brown and think, ok, all brown, no problems.

This would continue forever, as they never knew how many had blue eyes. They need to know that one or more has blue eyes, or it will not work. >>


That's why I like my variation better.

 

[calbear2000]

<< It will not work unless the "supreme being" tells them how many have blue eyes, why else would they need to know how to count.

If there were 10 on the island, 9 with brown, 1 with blue. The 9 would see the one with blue eyes and not kill themselves, the one with blue would only see brown, and would not kill himself. The next day, they would see the same thing, but the brown eyed peeps would still see one with blue eyes. The blue eyed dude would still see nothing but brown and think, ok, all brown, no problems.

This would continue forever, as they never knew how many had blue eyes. They need to know that one or more has blue eyes, or it will not work. >>



As I said, the original post states that there are 10 blue eyes. Thus the situation you describe is invalid.

Have a nice weekend all! Hopefully when I get back online Sunday night, there will be no more debate about the solution!

 

[911paramedic]

As I said, the original post states that there are 10 blue eyes. Thus the situation you describe is invalid.

YOU may have said that, but did the SUPREME BEING tell them that??? It is unclear in the riddle.

 

[calbear2000]

<<

<< It will not work unless the "supreme being" tells them how many have blue eyes, why else would they need to know how to count.

If there were 10 on the island, 9 with brown, 1 with blue. The 9 would see the one with blue eyes and not kill themselves, the one with blue would only see brown, and would not kill himself. The next day, they would see the same thing, but the brown eyed peeps would still see one with blue eyes. The blue eyed dude would still see nothing but brown and think, ok, all brown, no problems.

This would continue forever, as they never knew how many had blue eyes. They need to know that one or more has blue eyes, or it will not work. >>


That's why I like my variation better. >>



Yes but my variation has this extra component to think about... whether or not you have enough info Which you do!

 

[calbear2000]

<< As I said, the original post states that there are 10 blue eyes. Thus the situation you describe is invalid.

YOU may have said that, but did the SUPREME BEING tell them that??? It is unclear in the riddle. >>



Supreme doesn't need to tell them. They'll simple look around and realize there is more than 1 blue eye!!