Results 1 to 3 of 3

Math Help - counting

  1. #1
    Newbie
    Joined
    Jul 2007
    Posts
    6

    counting

    Q. How many paths are there when you move from (0,0) to (n,n) in the 1st quadrant of the graph, provided the constraint that you can move either one step above or one step right at any point of time.

    Is the ans (2n)!/n!n! ?
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor

    Joined
    Aug 2006
    Posts
    18,648
    Thanks
    1596
    Awards
    1
    Quote Originally Posted by kens View Post
    Q. How many paths are there when you move from (0,0) to (n,n) in the 1st quadrant of the graph, provided the constraint that you can move either one step above or one step right at any point of time.

    Is the ans (2n)!/(n!n!) ?
    YES
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Newbie
    Joined
    Jul 2007
    Posts
    6
    This is Pascal's triangle. you should find that the number of ways of getting to, say the point with coordinates (6,0) is 1, the nbr of ways of getting to (5,1) is 6, the nbr to get to (4,2) is 6C2, and so on. So the nbr of ways of getting to (3,3) is 6C3 which is 6!/3!3!.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. counting 1
    Posted in the Statistics Forum
    Replies: 1
    Last Post: September 8th 2011, 08:01 AM
  2. Counting
    Posted in the Discrete Math Forum
    Replies: 3
    Last Post: May 9th 2010, 04:34 AM
  3. Counting
    Posted in the Discrete Math Forum
    Replies: 1
    Last Post: March 9th 2010, 05:19 PM
  4. help on Counting
    Posted in the Discrete Math Forum
    Replies: 0
    Last Post: October 25th 2009, 08:51 AM
  5. Counting
    Posted in the Algebra Forum
    Replies: 2
    Last Post: August 10th 2009, 05:32 PM

Search Tags


/mathhelpforum @mathhelpforum