# One bullet, 100 prisoners: Can you crack this brain-teaser?

Originally published at: https://boingboing.net/2024/07/22/one-bullet-100-prisoners-can-you-crack-this-brain-teaser.html

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I let them go.

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Easiest brain teaser ever. Decriminalize drugs, release the related offenders, you’re down to one prisoner.

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No, I’m not; I’d never take such an amoral job, not even as a piss poor ‘thought experiment.’

# Legal slavery (aka, the US Prison system) is stillslavery.

This was a terrible topic for a “brain teaser”; please DO BETTER.

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Is this from the new Project 25 school curicula?

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Well I generally like riddles - but this seems rather nonsensical.

If a prisoner thinks there’s even a tiny chance they won’t get shot, they’ll try to run away.

Even if you had 1000 bullets, there is more than a tiny chance if 100 people scattered, some would get away.

So, I do hope Mark chimes in with the answer.

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I assume it is something like you announce that you will shoot the first person that tries to run away.

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There’s not enough information. This seems to be a variation of a (more defined) puzzle with five prisoners, whose solution is a bit wobbly but falls apart completely with 100 prisoners. Any “solution” would require re-defining the set-up with new information, at which point you’re basically making up your own problem to solve.

Oh no! They were Nazi war criminals! Who eat puppies and kittens for fun!

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Just tell them you will randomly shoot into the crowd (and randomly choose to shoot at the escapee) if any prisoner tries to escape. Since the prisoners are unwilling to take ANY risks, this would stop them from leaving.

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… should we wait until he tries to escape first?

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I have no immediate thoughts on this problem and really don’t want to dig into something that requires me to put myself into the shoes of one perfectly rational and emotionless agent of a carcerial state with perfect aim, supervising one hundred perfectly rational and emotionless prisoners.

When you have one hundred perfectly rational and emotionless prisoners who know that the guard only has one bullet, then you invite results like the prisoners voting on who the ten most-hated prisoners are, forcing those poor bastards into situations where the guard will need to use their one bullet, and then the other ninety-nine all flee, possibly with a diversion to murder the perfectly rational and emotionless guard with perfect aim in a perfectly rational and emotionless manner.

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But that isn’t what the riddle says. Quite the opposite.They run even if there is a tiny chance of success.

If a prisoner thinks there’s even a tiny chance they won’t get shot, they’ll try to run away. If a prisoner is sure they’ll get shot, they won’t run away.

I thought about it. The bullet is actually in a gun type nuclear device like Little Boy and will trigger a nuclear explosion.If anyone runs everyone dies.

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Despite the distasteful subject matter, I can’t help but try to solve it. Maybe there’s a logical solution, but something tells me it’s a “oh so clever” answer like firing the one round into the air to prove the gun is loaded, even though the scenario doesn’t actually give enough detail to conclude whether that would work.

Edit: Part of the reason I prefer riddles. Like, a well-written riddle the sphinx might ask you, not a 1960s Batman Riddler one where the answer is “a ballpoint banana” or something.

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This isn’t a brain-teaser. This is a ghoulish scenario that normalizes the dehumanization of incarcerated people.

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True to form for many of the brainteaser posts, I feel like it’s missing a couple of details that are necessary for it to be solvable. Is everyone aware of the lone-bullet issue, or just the guard? Would firing the one bullet into the air be enough to convince a group of rational people that they’ll definitely be fired upon if they run?

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“I’ve got a hundred bullets in this gun”, he lied.

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