Riddle Minute

[Doc Sigma]

Prisoner #10 counts the number of black hats. If it is even, he says white; if it is odd, he says black. He has a 50/50 chance of being right, but either way, everyone will know if he was right or wrong based on if he was killed or not. #9 can use this information to determine his own hat color: count the number of black hats he can see, and keep in mind that the total number of remaining black hats must be even if #10 said white and must be odd if #10 said black. Thus:

#9 sees an even number of black hats and #10 said white: #9's hat is white
#9 sees an even number of black hats and #10 said black: #9's hat is black
#9 sees an odd number of black hats and #10 said white: #9's hat is black
#9 sees an odd number of black hats and #10 said black: #9's hat is white

Thus, #9 can get his color right 100% of the time.

Going down the line, each prisoner will know the colors of all the hats behind him, as well as the ones in front of him that he can see, and whether the total number of black hats is odd or even, which is all the information anyone needs to figure out his own hat color.

Prisoners #1 through #9 live 100% of the time; prisoner #10 lives 50% of the time.

[nickspoon]

Absolutely correct. :)

[Doc Sigma]

MAD props on that one, Sir Nicholas. Figuring it out was satisfying and TONS of fun!

[LewisTheTank]

My name is eponymous with something in space,
I contain the last bit of the human race.
I am six miles long and five miles tall,
And I am four miles wide, if anything at all.

Within my self is a rather strange being,
With outdated fashion he is disagreeing.
Also inside me is a strange sort of man,
Made up of light; Quote regulations he can!

My main mission began when my story unfolds,
However three million years later we are told,
Are the highlights of tales of my worthy crew.
(Can you decipher these clues I am telling you?)

[LewisTheTank]

My name is eponymous with something in space,
I contain the last bit of the human race.
I am six miles long and five miles tall,
And I am four miles wide, if anything at all.

Within my self is a rather strange being,
With outdated fashion he is disagreeing.
Also inside me is a strange sort of man,
Made up of light; Quote regulations he can!

My main mission began when my story unfolds,
However three million years later we are told,
Are the highlights of tales of my worthy crew.
(Can you decipher these clues I am telling you?)

Don't tell me this is THAT hard for you guys/gals?
(Or is it?)