Results 1 to 5 of 5

Math Help - Combination question

  1. #1
    Newbie
    Joined
    Apr 2011
    Posts
    4

    Combination question

    There r 100 different balls in a bag.A person takes out balls one by one and then he puts them back.Next he takes out 10 balls at a time and the rest 90 one by one.He again puts them back.He next takes out 20 balls at a time and the rest 80 one by one.He repeats the same routine until he takes 100 balls at a time.Find the total number of ways in which a person can do these operations.

    please help...??
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Member
    Joined
    Jun 2010
    Posts
    205
    Thanks
    1
    I'm not sure I understand the question exactly, but here's my understanding: There are 100! ways to take them out one-at-a-time. There are 100 C 10 ways to choose the first ten, then of the remaining 90 there are 90! ways to choose those. Using this logic throughout, we would get 100! + (100 C 10)*90! + (100 C 20)*80! + ... + (100 C 90)*10!.

    Hope this is the right way to understand the problem.

    [Edit: Actually, rather than adding these we should probably multiply them since a difference in the way of doing the first selection constitutes a different overall process of selection.]
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Newbie
    Joined
    Apr 2011
    Posts
    4
    i also thought of the same it shld be multiplied i guess... becoz all the events are independent.... confirmed
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Newbie
    Joined
    Apr 2011
    Posts
    4
    also is there any way of calculating the exact figure.... exactly... Is there any such calculator that is availabel that can do it...
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Member
    Joined
    Jun 2010
    Posts
    205
    Thanks
    1
    I believe it should be multiplied.

    If you want to calculate this, go to wolframalpha.com and type into the text box 100!*(100choose10)*90!*(100choose20)*80!*...

    Or you can try to enter it by pi notation, product((100choose10n)(100-10n)!) from n=0.. 9

    I'm not sure if entering either of these will work. The first one might be too long to enter, and I'm not sure if the program will read the second one correctly. But if you play with it I think you can figure something out.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Combination question
    Posted in the Discrete Math Forum
    Replies: 2
    Last Post: August 28th 2011, 01:47 PM
  2. Combination question?
    Posted in the Statistics Forum
    Replies: 5
    Last Post: July 9th 2011, 02:17 PM
  3. Combination Question
    Posted in the Discrete Math Forum
    Replies: 4
    Last Post: October 6th 2009, 02:18 PM
  4. Combination - KEY QUESTION
    Posted in the Statistics Forum
    Replies: 1
    Last Post: November 23rd 2008, 04:43 PM
  5. Combination Question
    Posted in the Statistics Forum
    Replies: 5
    Last Post: January 13th 2007, 03:23 PM

Search Tags


/mathhelpforum @mathhelpforum