# The Grey Labyrinth is a collection of puzzles, riddles, mind games, paradoxes and other intellectually challenging diversions. Related topics: puzzle games, logic puzzles, lateral thinking puzzles, philosophy, mind benders, brain teasers, word problems, conundrums, 3d puzzles, spatial reasoning, intelligence tests, mathematical diversions, paradoxes, physics problems, reasoning, math, science.

Message body

 Emoticons View more Emoticons
 [quote="ralphmerridew"]Thought I mentioned this as a generalization: [spoiler]Beforehand, each person picks a different digit from 0 to 9. After they receive the hats, each assumes that digit is the last digit of the sum of all hats, and calculates what number is on his/her hat under that assumption. Exactly one of them will be right.[/spoiler][/quote]
Options
HTML is OFF
BBCode is ON
Smilies are ON
 Disable BBCode in this post Disable Smilies in this post

 All times are GMT
 Jump to: Select a forum Puzzles and Games----------------Grey Labyrinth PuzzlesVisitor Submitted PuzzlesVisitor GamesMafia Games Miscellaneous----------------Off-TopicVisitor Submitted NewsScience, Art, and CulturePoll Tournaments Administration----------------Grey Labyrinth NewsFeature Requests / Site Problems
 Topic review
Author Message
Antrax
Posted: Fri Jul 23, 2010 6:46 pm    Post subject: 1

Yeah, that's what I had as well. I thought it was cute, especially because I got to it from a much more complicated "iterative guessing" algorithm.
ralphmerridew
Posted: Fri Jul 23, 2010 11:53 am    Post subject: 0

Thought I mentioned this as a generalization:

Beforehand, each person picks a different digit from 0 to 9. After they receive the hats, each assumes that digit is the last digit of the sum of all hats, and calculates what number is on his/her hat under that assumption. Exactly one of them will be right.
Antrax
Posted: Fri Jul 23, 2010 6:34 am    Post subject: -1

I was actually a bit surprised that I haven't heard of this one until recently, it seems like a natural extension of the many other hat puzzles (one I asked about a while ago, in particular).
So, 10 people, 10 hats. Each hat has a single digit on it, digits can occur more than once. Let people confer, place hats on heads, every person guesses what digit the hat on his head bears without hearing other guesses and if at least one of them guesses correctly, profit.
What's the winning strategy?