the prison

I think I can't solve this because of lack of information. He probably use the other prisoners knowledge that they have white stickers, in order to pass.

We had a similar thing in school once when each of us got a sticker with one of four colors in our forehead, and we could not talk. I ended up organizing the others into groups, based on their colors, then another person could point me to the group I belonged to. If I couldn't talk in this case, I could just point at my teeth, and then at the person. If he is smart he should get it.
But of course there is no other interaction between these people i presume, so it is nothing like that.

Can you be a bit more exact as to what happens with the stickers? Does the guard use all of them? How does he distribute the stickers? Can one person get two black stickers and or two white? Can he overlap the stickers, so it is possible to see only one of two stickers on one persons back? Does each person have to have a sticker on his back?

They can only have 1 sticker: a white one or a black one.
No sticker overlapping, and the prisoners can't see wich 2 stickers aren't used.

This is the hint we got during history lesson: No one gets his freedom for free.

Ok, thanks. I like these kinds of riddles, hopefully I will have the solution some time today.

At first glance I would think that the only way that prisoner number 1 could know if he had a white sticker would be if the two others had black ones, then the second and Abraham would know that they have black ones. But this can not be because number 1 and 2 have white stickers.

Hi
this looks similar to the riddle posted and answers by malik basha on 1/27....

BTW greenbite - the term is "Nobel Prize Winner"

Nobel Prize
n.
Any of the six international prizes awarded annually by the Nobel Foundation for outstanding achievements in the fields of physics, chemistry, physiology or medicine, literature, and economics and for the promotion of world peace.

but it isn't

and i didn't know it was the nobel priZe winner.. not that familiar with english

ooooo, ok! A mytery!

where are you from?

Belgium

sorry it is indeed very similar to the one malik basha posted. didn't see that post of him. My apology, Chai Tea

Is it? In story it is, but the solution can't be the similar the way I see it. I managed to solve Malik Bashas quite fast. But this one is different.

And there is something that puzzles me. You said that "if the prisoners give the correct answer in 1 day they are released" and "If you have a white sticker on your back, you are released.".

Do you mean that "If the prisoner has a white sticker on his back AND finds out, then he can go free"? If he has a black sticker, is he then doomed, even if he finds out? Then there is no point in guessing black. But that doesn't make sense, because the first thing he said was that the prisoners are to be released if they give the right answer.

The way I understand this is that there are two ways of getting out. 1: You give the correct answer to what is on your back. That is quite clear from the first quote. 2: If you have a white sticker on your back. Like you said in the second quote. In this case I would of course tell the guard that I have a black sticker, because then I am guaranteed to get out. I might be wrong, then I have a white sticker and he must let me out to keep his promise. Or I was giving the correct answer to what was on my back, and I should therefore be released.

But I am also left wondering about something else from the first quote, it sounds like they must all give the correct answer in order to be able to get out. If I was Abraham I would think, wow I was lucky. They both guessed right for some reason, so now there is still a chance that we can all be right. The other possibility is that I have the white one. Then I should guess black for the same reason as stated above.

Do you mean that "If the prisoner has a white sticker on his back AND finds out, then he can go free". If he has a black sticker, is he then doomed, even if he finds out? But that doesn't make sense, because the first thing he said was that the prisoners are to be released if they give the right answer.

Perhaps they concluded that it would have been unfair to distribute two white stickers and one black sticker.