Results 1 to 2 of 2

Math Help - Combinations

  1. #1
    Newbie
    Joined
    Nov 2010
    Posts
    4

    Combinations

    Hi there,

    It's been a while since I've done questions like this and my mind has gone blank. I'm completely stumped about how I would start off a question like this. I vaguely remember that theres some formula and something to do with factorials that helps solve this but not too sure.


    "How many different possible combinations of 5 yellow balls and 6 red balls
    can be selected from a box of 7 yellow balls and 8 red balls?


    If anyone can point me in the right direction that would be great, I think I just need a slight refresher.

    Many thanks,
    If in doubt, rem
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor

    Joined
    Aug 2006
    Posts
    18,913
    Thanks
    1760
    Awards
    1
    Quote Originally Posted by monkeyhead View Post
    "How many different possible combinations of 5 yellow balls and 6 red balls can be selected from a box of 7 yellow balls and 8 red balls?
    Unless we assume that the balls are all different the question is meaningless.
    If the balls are different the answer is \binom{7}{5}\binom{8}{6}

    Where \binom{n}{k}=\frac{n!}{k!(n-k)!}
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Combinations in a set
    Posted in the Discrete Math Forum
    Replies: 3
    Last Post: September 9th 2010, 07:19 AM
  2. How many combinations are possible?
    Posted in the Discrete Math Forum
    Replies: 0
    Last Post: July 23rd 2009, 08:53 PM
  3. Combinations
    Posted in the Statistics Forum
    Replies: 2
    Last Post: May 5th 2008, 09:28 AM
  4. How many combinations..?
    Posted in the Algebra Forum
    Replies: 9
    Last Post: May 2nd 2008, 11:34 AM
  5. combinations
    Posted in the Discrete Math Forum
    Replies: 1
    Last Post: April 27th 2008, 10:00 AM

Search Tags


/mathhelpforum @mathhelpforum