Results 1 to 6 of 6

Math Help - Story Problem for 4th Grade Homework

  1. #1
    Newbie
    Joined
    Sep 2009
    Posts
    4

    Story Problem for 4th Grade Homework

    Eight runners are entered in the 1000-meter run. How many different first, second, and third place finishes could possibly occur? I have no idea how to start to help my daughter with this problem. Thanks for any help you can give this math-challenged mom.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Senior Member
    Joined
    Jul 2009
    Posts
    397
    Hi gitai

    Number of persons that can be the first = 8
    Number of persons that can be the second = 7 (because 1 person has finished first)
    Number of persons that can be the third = ....

    Have any ideas to continue?
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Newbie
    Joined
    Sep 2009
    Posts
    4

    Think we figured it out

    we found a combinations/permutations calculator on-line, so we said:
    Types to Choose (meaning how many runners): 8 = n
    Number Chosen (meaning first place, second place and third): 3 = r

    and repetition is not allowed meaning we used this formula:

    n!/(n-r)! = 8!/(8-3)!

    Now of course we needed to find out that ! is a factorial

    8! = 8x7x6x5x4x3x2x1 or 40,230
    (8-3) = 5! = 5x4x3x2x1 or 120

    40,230/120 = 336 possible combinations

    Are we correct?
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Senior Member
    Joined
    Jul 2009
    Posts
    397
    Hi gitai

    Absolutely correct
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Newbie
    Joined
    Sep 2009
    Posts
    4

    Yeah!

    Thank you Songoku! We are very proud of ourselves!
    Follow Math Help Forum on Facebook and Google+

  6. #6
    Newbie
    Joined
    Sep 2009
    Posts
    3
    Or if you want a more basic solution>

    Possible number of first place = 8
    Second place = 7
    Third place = 6

    (as songoku said)

    Therefore, possible combinations = 8 * 7 * 6 = 336
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 1
    Last Post: June 6th 2010, 10:51 PM
  2. 7th grade math homework precent problem
    Posted in the Algebra Forum
    Replies: 4
    Last Post: May 31st 2007, 11:55 AM
  3. % story problem....
    Posted in the Algebra Forum
    Replies: 1
    Last Post: April 22nd 2007, 03:38 PM
  4. Story Problem Help please
    Posted in the Calculus Forum
    Replies: 0
    Last Post: February 23rd 2007, 12:48 AM
  5. Story Problem
    Posted in the Trigonometry Forum
    Replies: 1
    Last Post: September 25th 2006, 08:56 PM

Search Tags


/mathhelpforum @mathhelpforum