Results 1 to 2 of 2

Math Help - Can any one explain this question to me, thxs.

  1. #1
    Newbie
    Joined
    Apr 2010
    Posts
    3

    Can any one explain this question to me, thxs.

    - From a box containing 3 white balls and 7 black balls, 30 balls are drawn with replacement. Find the probability of getting 9 and 10 white balls?

    I'm having a little bit of trouble finding how to work it out any help would be much appreciated.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor
    Joined
    Dec 2009
    Posts
    3,120
    Thanks
    1
    Quote Originally Posted by Funnel View Post
    - From a box containing 3 white balls and 7 black balls, 30 balls are drawn with replacement. Find the probability of getting 9 and 10 white balls?

    I'm having a little bit of trouble finding how to work it out any help would be much appreciated.
    Hi Funnel,

    this is binomial.

    As balls are being replaced, and there are 10 balls in total, the probabilities are always

    P(w)=0.3,\ P(b)=0.7

    Hence, you need to calculate the binomial term for 9 whites and 21 blacks,
    and seperately for 10 whites and 20 blacks

    \binom{30}{9}0.3^90.7^{21} or \binom{30}{21}0.7^{21}0.3^9

    \binom{30}{10}0.3^{10}0.7^{20} or \binom{30}{20}0.7^{20}0.3^{10}
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. plz explain this geometry question
    Posted in the Geometry Forum
    Replies: 2
    Last Post: February 24th 2011, 07:13 AM
  2. i want to explain the solution in this question
    Posted in the Pre-Calculus Forum
    Replies: 6
    Last Post: December 8th 2009, 08:22 AM
  3. Please explain this question
    Posted in the Calculus Forum
    Replies: 11
    Last Post: November 10th 2009, 04:38 PM
  4. A question to explain to a 10 year old
    Posted in the Algebra Forum
    Replies: 4
    Last Post: December 29th 2008, 08:44 AM
  5. Replies: 4
    Last Post: September 7th 2008, 11:07 PM

Search Tags


/mathhelpforum @mathhelpforum