Monks. (1 Viewer)

[seanieg89]

One hundred monks live on a remote island and live by very strict rules. Each is born with either blue or brown eyes.

1. They are forbidden from communicating with each other in any way.

2. They all eat their meals together during the day.

3. If a monk ever learns of the colour of his eyes during the day, he must commit suicide at midnight that night.

One day, a stranger lands on the island alone. He joins the monks and tries to learn their ways.
After a few months, he find their ways of silence too frustrating and leaves. As he leaves the island, he tells them all "At least one of you has blue eyes!".

(He may or may not have been telling the truth, but the monks all take his word as fact, for they have no notion of dishonesty.)


What happens to the monks now and why? (Hint: The monks are very intelligent.)


There is a follow up question that is more intriguing, but I will wait until someone can answer this one! It is all a question of logic, nothing silly and lateral.

 

[bleakarcher]

One hundred monks live on a remote island and live by very strict rules. Each is born with either blue or brown eyes.

1. They are forbidden from communicating with each other in any way.

2. They all eat their meals together during the day.

3. If a monk ever learns of the colour of his eyes during the day, he must commit suicide at midnight that night.

One day, a stranger lands on the island alone. He joins the monks and tries to learn their ways.
After a few months, he find their ways of silence too frustrating and leaves. As he leaves the island, he tells them all "At least one of you has blue eyes!".

(He may or may not have been telling the truth, but the monks all take his word as fact, for they have no notion of dishonesty.)


What happens to the monks now and why? (Hint: The monks are very intelligent.)


There is a follow up question that is more intriguing, but I will wait until someone can answer this one! It is all a question of logic, nothing silly and lateral.

Do the monks know that they are born with either blue or brown eyes?

 

[seanieg89]

Yep.

 

[Carrotsticks]

Haha I know this riddle, was the topic of discussion at work a while ago.

 

[seanieg89]

It's a classic, I have another really nice one I heard recently that I will post after.

 

[bleakarcher]

Do the monks do nothing?

 

[bleakarcher]

They do nothing if at least 2 monks have blues eyes, if only one monk has blue eyes from the 100 that monk finds out and kills himself?

 

[seanieg89]

Not quite but you are on to something. Something definitely happens, regardless of how many have blue eyes.

 

[SpiralFlex]

Are monks bald?

 

[Thief]

Well if there were 2 monks with blue eyes on the island.. the first monk would see the second monk and realise that he had blue eyes, and then waits a day to see if he kills himself. And then that monk realises that since the second monk didnt kill himself that there is another monk with blue eyes on the island ie him and so he would kill himself on the second day. And that second monk would also reach that conclusion.

Wait could that apply to all the monks on the island..?

 

[Carrotsticks]

Poor monks.

 

[seanieg89]

Well if there were 2 monks with blue eyes on the island.. the first monk would see the second monk and realise that he had blue eyes, and then waits a day to see if he kills himself. And then that monk realises that since the second monk didnt kill himself that there is another monk with blue eyes on the island ie him and so he would kill himself on the second day. And that second monk would also reach that conclusion.

Wait could that apply to all the monks on the island..?

Correct idea. If you can clearly express how this idea generalises then I will consider the question answered and drop the follow-up question, wherein lies the real mindfuck.

 

[lvella10]

Well if there were 2 monks with blue eyes on the island.. the first monk would see the second monk and realise that he had blue eyes, and then waits a day to see if he kills himself. And then that monk realises that since the second monk didnt kill himself that there is another monk with blue eyes on the island ie him and so he would kill himself on the second day. And that second monk would also reach that conclusion.

That's about as far as I got with this Lol

 

[seanieg89]

Getting from the case where 1 monk has blue eyes to the case where 2 monks have blue eyes is probably the most crucial step. Try to base an inductive argument on this.

 

[SunnyScience]

Well if there were 2 monks with blue eyes on the island.. the first monk would see the second monk and realise that he had blue eyes, and then waits a day to see if he kills himself. And then that monk realises that since the second monk didnt kill himself that there is another monk with blue eyes on the island ie him and so he would kill himself on the second day. And that second monk would also reach that conclusion.

Wait could that apply to all the monks on the island..?

You can apply this to the whole population in a chain-reaction?

 

[DAFUQ]

they eventually all commit suicide after 100days

 

[seanieg89]

You can apply this to the whole population in a chain-reaction?

Yep, can you please explain this "chain-reaction" a little more clearly though?

 

[RealiseNothing]

If there was only 1 blue eyed monk, he would kill himself staight away.

If there were 2, both of the blue eyed monks would know that if there was only 1 then that person would kill himself straight away, but this did not happen and therefore there must be atleast 2 blue eyed monks. But both blue eyed monks see 98 brown eyed monks and only 1 blue eyed monk leading to the conclusion they must have blue eyes and would therefore both kill themself.

If there were 3 blue eyed monks, each one would see that there are 2 blue eyes and 97 brown eyes. If there were only 2 blue eyes, then they would kill of killed themselves already. So there must be atleast 3 blue eyed monks, since they only see 2 others, it is obvious they must be the third.

This pattern continues up to the 'n' amount of blue eyed monks since they would know that if there were only 'n-1' blue eyed monks they would of already killed themselves, and hence there must be atleast 'n' blue eyed monks, but they only see 'n-1', so they conclude they are the 'n' blue eyed monk and kill themselves.

 

[deswa1]

You can apply this to the whole population in a chain-reaction?

This is what I think too. Lets say there are three monks all with blue eyes. Each sees that the other two have blue eyes and expects them to both kill themselves on the second day. When they don't, he realises that he must have blue eyes and kills himself. If though they do kill themselves on the second day, then he knows that he must have brown eyes and also kill himself.

 

[DAFUQ]

they eventually all know their eye colors and commit suicide after 100days