Results 1 to 4 of 4

Math Help - [SOLVED] Probablility

  1. #1
    Melinda
    Guest

    [SOLVED] Probablility

    A Carton of eggs contains three 55g eggs, five 59g eggs and two 52 g eggs. Work out the probability of choosing two 55 eggs at random?

    I would really appriciate it if someone could show me how to do this as i need to know it for an upcoming exam. Thankyou
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Super Member PaulRS's Avatar
    Joined
    Oct 2007
    Posts
    571
    Welcome, you are taking pairs I see, thus the possible outcomes are the 2-combinations (It doesn't matter the order) of those elements. The positive case is getting ( 55egg, 55egg )

    The number of possible cases is \binom{10}{2}
    And the positive ones, just 1

    Therefore : p(two 55 eggs) = \frac{1}{\binom{10}{2}}=\frac{1}{\frac{10!}{2!\cdo  t{8!}}}=\frac{1}{45}
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Super Member

    Joined
    May 2006
    From
    Lexington, MA (USA)
    Posts
    11,737
    Thanks
    642
    Hello, Melinda!

    There are two approaches to this problem (at least) . . .


    A carton of eggs contains three 55g eggs, five 59g eggs and two 52g eggs.
    Find the probability of choosing two 55g eggs at random
    I'll assume that the two eggs are drawn without replacement.


    [1] There are 10 eggs and 3 of them are 55g eggs.
    The probability that the first egg drawn is a "55" is: . \frac{3}{10}
    The probability that the second egg is a "55" is: . \frac{2}{9}
    . . Therefore: . P(\text{two 55s}) \:=\:\frac{3}{10}\cdot\frac{2}{9} \:=\:{\color{blue}\frac{1}{15}}


    [2] There are: . {10\choose2} \:=\:45 possible pairs of eggs that can be drawn.
    There are: . {3\choose2} \:=\:3 ways to draw two "55s".
    . . Therefore: . P(\text{two 55s}) \:=\:\frac{3}{45} \:=\:{\color{blue}\frac{1}{15}}

    Follow Math Help Forum on Facebook and Google+

  4. #4
    Super Member PaulRS's Avatar
    Joined
    Oct 2007
    Posts
    571
    Oh, I confused the number of 55g eggs with the 52 g eggs
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Basic Probablility
    Posted in the Statistics Forum
    Replies: 1
    Last Post: January 31st 2011, 09:51 AM
  2. probablility with balls
    Posted in the Statistics Forum
    Replies: 13
    Last Post: May 30th 2010, 12:57 PM
  3. probablility
    Posted in the Advanced Statistics Forum
    Replies: 1
    Last Post: April 16th 2008, 12:14 PM
  4. Quick question on probablility
    Posted in the Advanced Statistics Forum
    Replies: 5
    Last Post: January 26th 2008, 03:27 PM
  5. probablility...
    Posted in the Statistics Forum
    Replies: 4
    Last Post: May 24th 2007, 10:23 AM

Search Tags


/mathhelpforum @mathhelpforum