Creativity test
Moderators: Jay2k1, DavidM, amh
Hah, tricky.
Here's another, since the hat one doesn't seem to be too popular
There's an island where all of the people have either brown or blue eyes. It's a small island, and everybody knows everyone else, so everybody knows everyone else's eye color. However, nobody knows his own eye color, because there are no mirrors on the island. And nobody will tell anyone else his own eye color, because all of the inhabitants adhere to a strict religion which holds that if you learn your own eye color, you must commit suicide at the next midnight. The island being small and news traveling fast, all of the inhabitants will immediately learn of any suicides. All of the inhabitants are perfect logicians, meaning they will immediately make any deductions that can be made, and all of them are aware of all of these facts, including this one.
Once every 1000 years, a mystical green-eyed goddess appears on the hill outside town, and she always speaks the truth. All of the islanders gather around to hear her speak. On one occasion, she appeared, surveyed the crowd before her, and announced, "I see someone with blue eyes."
Describe in as much detail as possible what happens.
Here's another, since the hat one doesn't seem to be too popular
There's an island where all of the people have either brown or blue eyes. It's a small island, and everybody knows everyone else, so everybody knows everyone else's eye color. However, nobody knows his own eye color, because there are no mirrors on the island. And nobody will tell anyone else his own eye color, because all of the inhabitants adhere to a strict religion which holds that if you learn your own eye color, you must commit suicide at the next midnight. The island being small and news traveling fast, all of the inhabitants will immediately learn of any suicides. All of the inhabitants are perfect logicians, meaning they will immediately make any deductions that can be made, and all of them are aware of all of these facts, including this one.
Once every 1000 years, a mystical green-eyed goddess appears on the hill outside town, and she always speaks the truth. All of the islanders gather around to hear her speak. On one occasion, she appeared, surveyed the crowd before her, and announced, "I see someone with blue eyes."
Describe in as much detail as possible what happens.
Everyone will look at the blue eyed people, all blue eyed people will realise they have blue eyes and kill themselves. The ones that are left will realise they have brown eyes and therefore kill themselves
Now for something difficult
1,13,16,61,?,217
what is ? and why?
Now for something difficult
1,13,16,61,?,217
what is ? and why?
Last edited by Nicky on 18-07-2005 19:27, edited 1 time in total.
@Kisa: 20?
@Aghannor: One person has blue eyes. He sees that everyone else has brown eyes, so he kills himself. The rest of them now know that they all have brown eyes and kill themselves too.
@Aghannor: One person has blue eyes. He sees that everyone else has brown eyes, so he kills himself. The rest of them now know that they all have brown eyes and kill themselves too.
Last edited by nickspoon on 18-07-2005 19:27, edited 1 time in total.
@Nicky:
The only pattern I can is...
1 + 12 = 13
13 + 3 = 16
16 + 45 = 61
The numbers we're adding are 1 2 3 4 5, etc., so
61 + 67 = 128
128 + 89 + 217
which works, but the 13 + 3 one is kinda weird...
As for the blue eyes green eyes...
@Nicky & nickthespoon: you are correct that eventually all the brown eyed people will kill themselves, but you have the first half wrong. What if more than one person has blue eyes?
@Kisa: Assume she could see everyone's eyes. It is true that if there is more than one blue-eyed person, everyone will see someone with blue eyes, but eventually people will figure out their eye color.
Hint: What would happen if only one person had blue eyes? What if two people had blue eyes? What if three people blue eyes? Now generalize this...
The only pattern I can is...
1 + 12 = 13
13 + 3 = 16
16 + 45 = 61
The numbers we're adding are 1 2 3 4 5, etc., so
61 + 67 = 128
128 + 89 + 217
which works, but the 13 + 3 one is kinda weird...
As for the blue eyes green eyes...
@Nicky & nickthespoon: you are correct that eventually all the brown eyed people will kill themselves, but you have the first half wrong. What if more than one person has blue eyes?
@Kisa: Assume she could see everyone's eyes. It is true that if there is more than one blue-eyed person, everyone will see someone with blue eyes, but eventually people will figure out their eye color.
Hint: What would happen if only one person had blue eyes? What if two people had blue eyes? What if three people blue eyes? Now generalize this...