Questions tagged [hat-guessing]
Cooperative games where a team of players must try to guess the color of their hat, but can only see their teammates' hats.
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100 Dwarves and a tiny room
I've got this riddle from a friend at work.
Say we have 100 dwarves.
They all receive little dwarven shirts with numbers between 0-99 (With repetitions), and after that they all enter into a room. (...
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Hat Guessing Game in Vegas
A team of 10 people are going to play a cooperative game. While their eyes are closed, a pit boss will place either a red or green hat on each of their heads, chosen by fair coin flip. They then all ...
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Cooperative guessing game: no incorrect guesses
There are 15 players who will play a cooperative game. They begin by closing their eyes. A referee will place either a black hat or a white hat (chosen by fair coin flip) on each player's head. The ...
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N people, N hat colors, and a One-Way Glass
This is a variant of this question, reproduced below:
There are $n$ people, who will stand in a circle while a game master places a hat on each of their heads. The hats can each be one of $n$ colors (...
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Alternating Hat Colors
A prison warden offers his inmates a game for their freedom. He will secretly write a number on each of their foreheads, with no two foreheads having the same number. The inmates get to look around, ...
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5 logicians with 1 or 2 hats (Part II) [8,9,10]
This is the corrected version of this question.
There are 5 logicians seated around a table. They are blindfolded and hats are placed on their heads. After removing the blindfolds, they are told a ...
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Five Haberdashers
This is yet another hat puzzle, but not one of the usual ones! Key differences/commonalities between other hat puzzles are emphasized.
Five friends are going to go on a game show. When the game ...
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Five hats and four logicians in a circle
I found this question in a book. The solution is correct (and complicated). No tricks involved.
Four men were seated around a table. They were blindfolded and a
colored hat was placed on each of ...
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1000 logicians wearing hats
Pre-game: There are 1000 logicians in a line, each wearing a black or a red hat, completely at random. No one knows the color of their own hat. Each can see the hats on the next 10 people. The ...
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Infinitely many dwarves wearing hats of 2 colours
I have heard of the puzzle with 100 or 10 dwarves wearing a hat of a color, either red or blue, and standing in a straight line, and having to guess the color of their own hat - it's quite easy.
The ...
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The sadistic executioner (a.k.a the 100 prisoners) [duplicate]
100 prisoners are sent into a room to hear the warden say: "tomorrow I will line you up and put a hat on your head. The hat can be red, green, yellow, …" and he goes on enumerating colors. He then ...
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Of men and hats
There's an obvious generalization of this problem: There are a rather large number of prisoners, each of them seeing the color of the hat of all the following sad fellows bot not their; the hats may ...
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Four prisoners wearing black and white hats
There are four prisoners. All four prisoners will be freed, if at least one of them correctly guesses the color of the hat on his head.
They can't speak to each other, and they can't touch each other.
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Hats and Aliens
Here's a neat little puzzle taken from a Google interview question:
10 humans are abducted by aliens; each represents 10% of the entire human population. The aliens give each abductee either a purple ...
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N logicians wearing hats of N colors
N logicians are wearing hats which can be of N different colors (each hat has one color; there can be multiple hats with the same color). Each logician can see the colors of all hats except his own. ...
