Results 1 to 3 of 3

Math Help - Russian Roulette Based Puzzle

  1. #1
    Member
    Joined
    Sep 2007
    Posts
    75

    Russian Roulette Based Puzzle

    The mafia has kidnapped you and says that if you answer a question of theirs correctly that they will let you go free:

    There are 4 guns on a table in front of you and another is being held to your head. Of the 5, one gun has 1 chamber, one has 2 chambers, one has 3, another 4 and the last has 5 chambers.

    The person holding the gun to your head says that he chose it at random amongst the other 4 and put a random amount of bullets in it from 1 to the amount of chambers that were available.

    The question you have to answer to avoid risking death is: If he pulls the trigger once, what is the chance that you will be shot and die regarding the information you have been presented with?
    Last edited by Obsidantion; August 17th 2008 at 10:23 AM.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor Quick's Avatar
    Joined
    May 2006
    From
    New England
    Posts
    1,024
    actually I think that you have 50% chance if he picks a gun with more than one round in it and 100% chance if he picks the gun with just the one chamber.

    So that would mean the total odds would be: 1\cdot \frac{1}{5} + .5\cdot \frac{4}{5}

    So I say that you have a 3/5 chance of dying, or 60%
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Member
    Joined
    Sep 2007
    Posts
    75
    Quote Originally Posted by Quick View Post
    actually I think that you have 50% chance if he picks a gun with more than one round in it
    Say he picks the gun with 2 rounds/chambers, he'll fill it with either 1 or 2 bullets (not 0) which would lead to one of three outcomes:
    -1 bullet loaded, loaded chamber fired (1/4 chance)
    -1 bullet loaded, unloaded chamber fired (1/4 chance)
    -2 bullets loaded, loaded chamber fired (1/2 chance)

    Meaning a 3/4 chance of death.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Puzzle based on Turan's Theorem
    Posted in the Discrete Math Forum
    Replies: 0
    Last Post: October 30th 2010, 02:38 AM
  2. Tricky russian statistic problem
    Posted in the Advanced Statistics Forum
    Replies: 2
    Last Post: October 2nd 2010, 08:46 AM
  3. Russian Roulette Statistics
    Posted in the Advanced Statistics Forum
    Replies: 2
    Last Post: September 9th 2008, 07:59 PM
  4. russian roulette
    Posted in the Advanced Statistics Forum
    Replies: 4
    Last Post: August 9th 2008, 06:53 PM
  5. Russian Puzzle
    Posted in the Math Challenge Problems Forum
    Replies: 3
    Last Post: February 16th 2007, 03:30 AM

Search Tags


/mathhelpforum @mathhelpforum