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Logic puzzle: Russian Roulette

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Here is another logic puzzle, see what you think:

You are tied to your chair and can't get up. Here's a gun. Here's the barrel of the gun, six chambers, all empty. Now watch me as I put two bullets in the gun. See how I put them in two adjacent chambers? I close the barrel and spin it. I put the gun to your head and pull the trigger. Click. You're still alive. Lucky you! I'm going to pull the trigger one more time. Which would you prefer, that I spin the barrel first, or that I just pull the trigger?

Comments

  • Anonymous
    August 10, 2008
    PingBack from http://www.easycoded.com/logic-puzzle-russian-roulette

  • Anonymous
    August 10, 2008
    spin it.(but ,actually it wont make a difference because there are only two chances hit or miss)

  • Anonymous
    August 10, 2008
    Spin it again (33% is better than 40%)

  • Anonymous
    August 11, 2008
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  • Anonymous
    August 11, 2008
    Spin, That leaves me a one in six chance of the barrel being full, otherwise I am left with a 1 in five chance

  • Anonymous
    August 11, 2008
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  • Anonymous
    August 11, 2008
    I'd prefer it if you just pulled the trigger

  • Anonymous
    August 11, 2008
    The donut was was interesting - now this is a little creepy....

  • Anonymous
    August 11, 2008
    Always spin the barrel before you shoot, the fact that the first was an empty slot means you have reduced odds for the next shot. At best you are 3/5 to live, a fresh spin is 2/3 to live. My math may be fuzzy, however

  • Anonymous
    August 11, 2008
    After spinning there is a 1/3 chance of the chamber being filled. After firing the first time and it being blank I can now eliminate the which chamber is next by two. It can't be the blank chamber that was just fired and it can't be the second of the two loaded chambers. It's possible that the blank that was just fired is the one after the loaded chambers leaving me with a ratio of loaded/onloaded chambers of 1/4. Just pull the trigger again.

  • Anonymous
    August 11, 2008
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  • Anonymous
    August 11, 2008
    I'm not much of a stats guy but I'd say just pull it again. Please post the analysis behind your question!

  • Anonymous
    August 11, 2008
    I think just pull the trigger (this has probability of 1/4) while spinning the barrel will have probability 2/6)

  • Anonymous
    August 11, 2008
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  • Anonymous
    August 11, 2008
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  • Anonymous
    August 11, 2008
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  • Anonymous
    August 11, 2008
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  • Anonymous
    August 11, 2008
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  • Anonymous
    August 11, 2008
    If you click next then your chances to get empty slot is 3 out of 6 while if you spin it's 4 out of 6, so spinning always wins. Variance in number of chambers shall have no effect on logic so if you had only 3 chambers then spinning will be the only chance to stay alive.

  • Anonymous
    August 11, 2008
    I would prefer you spin. If you spin I have a 4/6 chance that it'll be a blank chamber. If you pull I have a 3/5 chance which is slightly less that if you spin. Am I right?

  • Anonymous
    August 11, 2008
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  • Anonymous
    August 11, 2008
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  • Anonymous
    August 11, 2008
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  • Anonymous
    August 11, 2008
    Spin it again so my odds are increased of another empty chamber being fired since you will be putting the previously fired round back into play.

  • Anonymous
    August 11, 2008
    Uh, perhaps we could talk this out! How about I buy you a beer, instead??

  • Anonymous
    August 11, 2008
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  • Anonymous
    August 11, 2008
    The probability of the next chamber being full is 2/5.  If you spin, the probability is 2/6.  That's a 7% greater chance of living if you spin it.

  • Anonymous
    August 11, 2008
    Spin it so you have a chance at getting the empty chamber you've just used.

  • Anonymous
    August 11, 2008
    If I'm in this situation, I tell you to just pull the trigger. I like my odds of survival better.

  • Anonymous
    August 11, 2008
    Please don't spin. You have a 1/3 chance of having one at the spin. 1/5 if you don't. (I think that's right anyway)

  • Anonymous
    August 11, 2008
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  • Anonymous
    August 11, 2008
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  • Anonymous
    August 11, 2008
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  • Anonymous
    August 11, 2008
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  • Anonymous
    August 11, 2008
    Just pull the trigger again.  The chances of the next chamber being empty is 3:1.

  • Anonymous
    August 11, 2008
    You'll laugh, but I found it easier to solve by brute-forcing a solution in C# than to think about it logically :-) In a million iterations, without spinning you get 75% of survival (3/4) and with spinning you get 67% of survival (2/3).  So it's best if you don't spin the barrel.

  • Anonymous
    August 11, 2008
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  • Anonymous
    August 11, 2008
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  • Anonymous
    August 11, 2008
    spin the barrel and hope the gravity is on my side :)

  • Anonymous
    August 11, 2008
    I would spin the barrel because that increases my chance of survival by 6.67%. So if you were not spinning the barrel my surival chance was 60% (3100/5). But the moment I asked you to spin the barrel, I increased my chance of survival to 66.67%(4100/6). Make sense?

  • Anonymous
    August 11, 2008
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  • Anonymous
    August 11, 2008
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  • Anonymous
    August 11, 2008
    I would prefer if its my turn now... You have an equal chance on landing on any of the 4 empty chambers. Only only will be lethal on the next shot... So my chance of survival would be 75%, vs 2/3 on a spin I think dont spin it...

  • Anonymous
    August 11, 2008
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  • Anonymous
    August 11, 2008
    Do what you want - it's Russian Roulette, and as I've had my turn - it's yours next - so go ahead, you decide!!!

  • Anonymous
    August 11, 2008
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  • Anonymous
    August 11, 2008
    I'd prefer you just pull the trigger. after the first empty shot, there are only 4 potential positions the chamber could be in, with 3 being safe, or 75% chance of living. Spinning it would result in 4/6 being safe, or 66%. It's only a 9% gain, but every bit helps :)

  • Anonymous
    August 11, 2008
    Spin it again... It anyway a game of chance.. Not spinning again decrease the chance while spinning it again may increase the chance...

  • Anonymous
    August 11, 2008
    Pull the trigger.  There's only a 1-in-5 chance I'll be shot.  If you spin again, it's 1-in-3...

  • Anonymous
    August 11, 2008
    Just pull the trigger again. There's only one of the four chambers that was empty which is followed by a round. Given that we know the first chamber was empty, there's a 25% probability that it was the one chamber followed by a round. (Or if we didn't know it was empty, it's a 16% probability that you hit the one before the live round) If you spin it again, there's a 33% probability you'll hit a live one.

  • Anonymous
    August 11, 2008
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  • Anonymous
    August 11, 2008
    Shoot me twice. If the first one hasn't killed me,i still have hope the second one will. but its only a 1 in 4 chance.

  • Anonymous
    August 11, 2008
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  • Anonymous
    August 11, 2008
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  • Anonymous
    August 11, 2008
    I'd say you spin the barrel first because that increases the chances of aligning the empty chamber with the trigger. In this case I have better chances as this means getting 4 out 6 chambers to survive (4/6 = 2/3 = 66%) The second option of just pulling the trigger has lesser chances of me surviving as one empty chamber has already been consumed and now I have just 3 out of 5 chambers to survive (3/5 = 60%).

  • Anonymous
    August 11, 2008
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  • Anonymous
    August 11, 2008
    That's simple: spinning the barrel again giving me a second 3-1 chance of survival as opposed to a 2:1 chance of survival without the second spin.

  • Anonymous
    August 11, 2008
    The pin is now in an empty chamber, one of a row of four. The chance that the next chamber is empty, is 3 out of 4 (75%). Spinning the barrel gives a chance of an empty chamber of 4 out of 6 (66.6%), so the best bet is to pull the trigger again. My preference would be to meet you in another situation :-)

  • Anonymous
    August 11, 2008
    Well mathematically speaking the probability of being shot is 1/3. After the first miss, it becomes 2/5 - hmmm, slightly higher. Maths isn't everything but hey, I'll take a spin.

  • Anonymous
    August 12, 2008
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  • Anonymous
    August 12, 2008
    Spin barrel first because I atleast have a chance at the same empty chamber.

  • Anonymous
    August 12, 2008
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  • Anonymous
    August 12, 2008
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  • Anonymous
    August 14, 2008
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  • Anonymous
    August 15, 2008
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  • Anonymous
    August 20, 2013
    Take the next shot (75% chance that you survive as it is impossible that one of the loaded chamber can be used)