Results 1 to 2 of 2

Math Help - Marbles and Probability

  1. #1
    Senior Member nycmath's Avatar
    Joined
    Jan 2013
    From
    Bronx, NY
    Posts
    395
    Thanks
    4

    Marbles and Probability

    A bag of marbles contains 10% brown, 10% red, 20% yellow, 20% blue, 20% orange and 20% green.

    Given the information about the distribution, now consider you pick 4 marbles in a row.

    What is the probability that:

    a. all 4 are blue?
    b. at least one is red?
    c. the forth chosen is the first to be brown?
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor
    Joined
    Nov 2013
    From
    California
    Posts
    2,182
    Thanks
    832

    Re: Marbles and Probability

    I don't think this is enough information to answer this. Suppose there are 100 marbles.

    The probability of selecting a blue marble on the first pick is $\frac{1}{5}$

    The probability of selecting a blue marble on the second pick is $\frac{19}{99}$

    3rd pick $\frac{18}{98}$, 4th $\frac{17}{97}$

    The product of these is 0.00123558.

    Now suppose there are 1000 marbles.

    These probabilities become $\frac{1}{5}, \frac{199}{999}, \frac{198}{998}, \frac{197}{997}$

    and the product of these is 0.00156179

    in the limit as $N \to \infty$ you'd expect that the probability of selecting 4 blues becomes

    $\left(\frac{1}{5}\right)^4=\frac{1}{625}=0.0016$
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Probability with marbles.
    Posted in the Statistics Forum
    Replies: 3
    Last Post: March 24th 2012, 02:10 AM
  2. Replies: 4
    Last Post: December 11th 2011, 10:05 AM
  3. Marbles in a jar (probability)
    Posted in the Statistics Forum
    Replies: 1
    Last Post: February 25th 2011, 12:25 AM
  4. Picking Marbles from a bag--Probability
    Posted in the Statistics Forum
    Replies: 5
    Last Post: February 24th 2011, 05:51 PM
  5. [SOLVED] Probability with Marbles
    Posted in the Statistics Forum
    Replies: 0
    Last Post: October 22nd 2009, 06:25 PM

Search Tags


/mathhelpforum @mathhelpforum