Results 1 to 3 of 3

Math Help - Probability help with marble!

  1. #1
    valo4212
    Guest

    Probability help with marble!

    A box contains 3 red marbles, 6 blue marbles, and 1 white marble. The marbles are selected at random, one at a time, and are not replaced. Find the probability.
    P(blue and red)
    P(white and blue)
    P(red and white)
    P(red and white and blue)
    P(red and red and blue)
    P(red and blue and blue)
    P(red and red and red)
    P(white and blue and blue)
    P(white and red and red)
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Global Moderator

    Joined
    Nov 2005
    From
    New York City
    Posts
    10,616
    Thanks
    9
    Quote Originally Posted by valo4212 View Post
    A box contains 3 red marbles, 6 blue marbles, and 1 white marble. The marbles are selected at random, one at a time, and are not replaced. Find the probability.
    P(red and white and blue)
    I do this one and leave the other as excersises.

    How many ways are there of choosing 3?
    In total we have 3+6+1=10.
    Thus, 10C3=120

    How many ways of choosing 1 white, 1C1=1
    Similarly, red: 3C1=3 and blue: 6C1=6.
    Thus, there are (1)(3)(6)=18 different ways of choosing red,white and blue.

    The probability therefore is,
    18/120=3/20=15%
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Super Member

    Joined
    May 2006
    From
    Lexington, MA (USA)
    Posts
    11,678
    Thanks
    610
    Hello, valo4212!

    A box contains 3 red marbles, 6 blue marbles, and 1 white marble.
    The marbles are selected at random, one at a time, and are not replaced.
    Find the probabilities.

    From the wording of the problems,
    . . I assume that the colors are drawn in that order.

    . . . . . . . . . . . . . . . 6 . .3 . . . . .1
    (1) .P(B and R) . = . --- --- . = . --
    . . . . . . - - - . . . . . 10 . .9 . . . . .5


    . . . . - - - . . . . . . . . 1 . . 6 . . . . 1
    (2) .P(W and B) . = . --- . -- . = . ---
    . . . . . . - - - . . . . . .10 . .9 . . . .15


    Want to try the rest of them now?

    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. red marble
    Posted in the Statistics Forum
    Replies: 1
    Last Post: October 12th 2011, 04:10 PM
  2. Replies: 1
    Last Post: February 18th 2010, 01:54 AM
  3. marble rollin
    Posted in the Math Topics Forum
    Replies: 1
    Last Post: September 10th 2009, 06:34 PM
  4. Direction a marble would travel on a plane
    Posted in the Geometry Forum
    Replies: 5
    Last Post: May 22nd 2009, 02:22 PM
  5. probability marble question
    Posted in the Statistics Forum
    Replies: 3
    Last Post: May 28th 2006, 01:45 PM

Search Tags


/mathhelpforum @mathhelpforum