Results 1 to 2 of 2

Math Help - Basic Probability Has Me Stumped

  1. #1
    Newbie
    Joined
    Dec 2008
    Posts
    1

    Exclamation Basic Probability Has Me Stumped

    Hey everyone,

    So I feel stupid, but I just can't figure this out. I have an exam tomorrow and one of the practice questions is as follows; it's broken into two parts:

    Part One:

    To play the Cash 5 lottery you must select 5 different numbers from a field of numbers from 1 - 40. Calculate your chances of winning the jackpot; getting 5 out of 5 correct.

    This one was simple enough

    40 x 39 x 38 x 37 x 36
    --------------------- = 658,008
    5!

    So it's a 1:658,008 chance of winning. Simple enough.

    Now part two asks the chances of getting 4 out of 5 correct. This has me stumped... I know it should work out to 1:3,760 but I cannot figure out how... If someone could help I'd greatly appreciate it.

    Thanks in advance
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Eater of Worlds
    galactus's Avatar
    Joined
    Jul 2006
    From
    Chaneysville, PA
    Posts
    3,001
    Thanks
    1
    We are choosing 4 from the 5 winning balls and 1 from the other 35 which are not winners.

    \frac{C(5,4)\cdot C(35,1)}{C(40,4)}

    BTW, for the first one, odds would be 1:658007

    You win once for every 648007 times you lose.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 2
    Last Post: March 3rd 2010, 01:25 PM
  2. Basic probability #2
    Posted in the Statistics Forum
    Replies: 0
    Last Post: October 2nd 2009, 01:06 PM
  3. Basic probability #3
    Posted in the Statistics Forum
    Replies: 0
    Last Post: October 2nd 2009, 01:06 PM
  4. [SOLVED] Simple Probability has me stumped
    Posted in the Statistics Forum
    Replies: 25
    Last Post: August 28th 2009, 01:39 PM
  5. Basic probability...
    Posted in the Statistics Forum
    Replies: 4
    Last Post: February 9th 2009, 09:07 AM

Search Tags


/mathhelpforum @mathhelpforum