Results 1 to 4 of 4
Like Tree1Thanks
  • 1 Post By Plato

Math Help - slot machine

  1. #1
    Newbie
    Joined
    Dec 2012
    From
    hwaii
    Posts
    3

    slot machine

    Is it conditional probability or not? What is the result?

    You walk into a Las Vegas casino. There are 10 slot machines. 9 of them win 20% of the time. 1 of them, the lucky machine, wins 30% of the time. But you don't know which one is the lucky one (the 30% winner). You watch someone put a quarter into the machine and win. What is the chance it was the "lucky" machine?
    Express your answer as a fraction or as a decimal with 2 significant digits
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor

    Joined
    Aug 2006
    Posts
    18,605
    Thanks
    1574
    Awards
    1

    Re: slot machine

    Quote Originally Posted by aloha View Post
    Is it conditional probability or not? What is the result?
    You walk into a Las Vegas casino. There are 10 slot machines. 9 of them win 20% of the time. 1 of them, the lucky machine, wins 30% of the time. But you don't know which one is the lucky one (the 30% winner). You watch someone put a quarter into the machine and win. What is the chance it was the "lucky" machine?

    The question asks for the probability of using the lucky machine given a win.

    Or \mathcal{P}(L|W). We know \mathcal{P}(W)=\mathcal{P}(L\cap W)+\mathcal{P}(L^c\cap W).

    As this is not a homework service, you must do the rest for yourself.
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Newbie
    Joined
    Dec 2012
    From
    hwaii
    Posts
    3

    Re: slot machine

    I calculated P(L|W)= 1/10*30/100= 3/100.
    I don't understand why you included the winning chance of the machines ? 1/10* 30% * 9/10*20% ?
    Follow Math Help Forum on Facebook and Google+

  4. #4
    MHF Contributor

    Joined
    Aug 2006
    Posts
    18,605
    Thanks
    1574
    Awards
    1

    Re: slot machine

    Quote Originally Posted by aloha View Post
    I calculated P(L|W)= 1/10*30/100= 3/100.
    I don't understand why you included the winning chance of the machines ? 1/10* 30% * 9/10*20% ?
    Well that is completely wrong. This is Bayesian conditioning question.

    \mathcal{P}(L|W)=\frac{\mathcal{P}(L\cap W)}{\mathcal{P}(L\cap W)+\mathcal{P}(L^c\cap W)}.
    Thanks from aloha
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Enigma machine
    Posted in the Advanced Math Topics Forum
    Replies: 1
    Last Post: November 27th 2011, 10:35 PM
  2. Replies: 1
    Last Post: May 2nd 2010, 01:10 PM
  3. 3 Reel slot odds!
    Posted in the Advanced Statistics Forum
    Replies: 0
    Last Post: March 3rd 2010, 04:52 AM
  4. Mathematica - Slot (#n)
    Posted in the Math Software Forum
    Replies: 1
    Last Post: January 13th 2009, 02:21 PM
  5. Replies: 2
    Last Post: November 26th 2008, 05:17 PM

Search Tags


/mathhelpforum @mathhelpforum