Results 1 to 2 of 2

Math Help - Basic probability issues!

  1. #1
    Junior Member
    Joined
    Feb 2009
    From
    Fiery pits of confusion
    Posts
    36

    Basic probability issues!

    In a bingo game, balls numbered 1-75 are placed in a bin. Balls are randomly drawn and not repalced. Find each probability for the first 5 balls drawn.
    11. P(selection 5 two digit numbers): (22/25)(21/24)(20/23)(19/22)(18/21)=.495 (but this is not what's in the back of the book?)
    13. P(5 even numbers or 5 numbers less than 30)...I don't think I'm using the proper logic in finding the probability of even numbers or numbers less than 30. I'm going to omit my work for that reason..

    Thanks!
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Super Member

    Joined
    May 2006
    From
    Lexington, MA (USA)
    Posts
    11,909
    Thanks
    767
    Hello, puzzledwithpolynomials!

    In a Bingo game, balls numbered 1-75 are placed in a bin.
    Balls are randomly drawn and not replaced.
    There are: . {75\choose5} \:=\:17,\!259,\!390 possible outcomes.



    Find each probability for the first 5 balls drawn.

    11. P(5 two-digit numbers)
    There are 66 two-digit numbers (from 10 to 75).

    There are: . {66\choose5} \:=\:496,496 ways to get 5 two-digit numbers.

    Therefore: . P(\text{5 two-digit numbers}) \:=\:\frac{496,\!496}{17,\!259,\!390} \;\approx\;0.0288




    13. P(5 even numbers or 5 numbers less than 30)
    There are: . \begin{array}{c}\text{37 even numbers} \\ \text{29 numbers less than 30} \\ \text{14 even numbers less than 30}\end{array}

    Hence, there are: . 37 + 29 - 14 \:=\:52 numbers which are even or less than 30.

    And there are: . {52\choose5} \:=\:2,598,960 ways to get a number which is even or less than 30.


    Therefore: . P(\text{even or less than 30}) \;=\;\frac{2,\!598,\!960}{17,\!259,\!309} \;\approx\;0.1506

    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. basic probability
    Posted in the Statistics Forum
    Replies: 1
    Last Post: April 20th 2010, 07:06 AM
  2. Re: basic probability
    Posted in the Advanced Statistics Forum
    Replies: 2
    Last Post: March 26th 2010, 09:50 PM
  3. Basic Probability
    Posted in the Statistics Forum
    Replies: 4
    Last Post: September 25th 2009, 05:19 PM
  4. basic probability
    Posted in the Advanced Statistics Forum
    Replies: 5
    Last Post: July 15th 2008, 09:25 AM
  5. Please help with basic issues
    Posted in the Advanced Statistics Forum
    Replies: 10
    Last Post: April 14th 2008, 04:34 PM

Search Tags


/mathhelpforum @mathhelpforum