Results 1 to 2 of 2

Math Help - Probabilty: Some Answers That Need Checking Part 2

  1. #1
    Newbie stmsnyder1's Avatar
    Joined
    Feb 2009
    From
    Hawaii- at least in my dreams.
    Posts
    11

    Probabilty: Some Answers That Need Checking Part 2

    Hi,


    If anyone can please check what I have done, that would be awesome,

    70. Cross Country: There are three schools competing in a cross country race. School A has six runners. School B has five runners. School C has four runners. For scoring purposes, the race only considers the school of each runner. How many different finishing orders are there for the fifteen runners?

    I'm not quite sure how to do this. I believe the answer is 15!, but I am not sure.


    Newspaper: Your school has an editor in chief, and an assistant editor in chief. The staff of the newspaper has twelve students. In how many ways can students be chosen for these two positions? A combination is used to solve the problem. There are 66 ways that students can be chosen for the two positions.


    Student Council: Five representatives from a senior class of 280 students can be chosen to represent student council. In how many ways can students be chosen to represent student council?


    Thank you very much
    Isabel
    Last edited by mr fantastic; February 7th 2009 at 01:20 PM. Reason: Distrbuted questions over several threads.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Flow Master
    mr fantastic's Avatar
    Joined
    Dec 2007
    From
    Zeitgeist
    Posts
    16,948
    Thanks
    5
    Quote Originally Posted by stmsnyder1 View Post
    Hi,


    If anyone can please check what I have done, that would be awesome,

    70. Cross Country: There are three schools competing in a cross country race. School A has six runners. School B has five runners. School C has four runners. For scoring purposes, the race only considers the school of each runner. How many different finishing orders are there for the fifteen runners?

    I'm not quite sure how to do this. I believe the answer is 15!, but I am not sure. Mr F says: {\color{red}\frac{15!}{6! \cdot 5! \cdot 4! }}.


    Newspaper: Your school has an editor in chief, and an assistant editor in chief. The staff of the newspaper has twelve students. In how many ways can students be chosen for these two positions? A combination is used to solve the problem. There are 66 ways that students can be chosen for the two positions.

    Mr F says: Since the order is important (Mary as chief and Bob as Assistant is different to Bob as Chief and Mary as Assistant) it's a permutations problem: {\color{red}^{12}P_2}.


    Student Council: Five representatives from a senior class of 280 students can be chosen to represent student council. In how many ways can students be chosen to represent student council?

    Mr F says: Since the order is not important it's a combinations problem: {\color{red}^{280}C_5}.


    Thank you very much
    Isabel
    ..
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Statistical and probabilty questions part 1
    Posted in the Advanced Statistics Forum
    Replies: 0
    Last Post: September 27th 2009, 01:58 PM
  2. Statistical and probabilty questions part 2
    Posted in the Advanced Statistics Forum
    Replies: 0
    Last Post: September 27th 2009, 01:58 PM
  3. Replies: 1
    Last Post: February 7th 2009, 04:41 PM
  4. Replies: 0
    Last Post: February 7th 2009, 12:36 PM
  5. checking my answers !! please have a look!!
    Posted in the Statistics Forum
    Replies: 2
    Last Post: October 30th 2006, 04:29 PM

Search Tags


/mathhelpforum @mathhelpforum