Results 1 to 5 of 5

Math Help - permutations

  1. #1
    Newbie
    Joined
    Jan 2010
    Posts
    4

    permutations

    hi,
    i have a problem in permutations

    how many word with or without meaning can be formed from the letters of the word TRIANGLE so that
    i) order of vowels remains the same
    ii)relative positions of vowels and consonants doesnt change..
    Last edited by sudhanshu; January 23rd 2010 at 03:22 AM. Reason: type error
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor

    Joined
    Aug 2006
    Posts
    18,649
    Thanks
    1597
    Awards
    1
    Quote Originally Posted by sudhanshu View Post
    how many word with or without meaning can be formed from the letters of the word TRIANGLE so that
    i) order of vowels remains the same
    ii)relative positions of vowels and consonants doesnt change..
    There are 3!=6 ways to arrange the vowels.
    In each 'word' there is only one way for "I_A_E" to appear in that order.
    So the answer to i) is \frac{8!}{6}.

    Now you try part ii).
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Newbie
    Joined
    Jan 2010
    Posts
    4
    Quote Originally Posted by Plato View Post
    There are 3!=6 ways to arrange the vowels.
    In each 'word' there is only one way for "I_A_E" to appear in that order.
    So the answer to i) is \frac{8!}{6}.

    Now you try part ii).
    ---------------------------------------------------------------
    sir,


    i have tried the first part as follows

    ***** I *****A*****E*****
    here * denotes the positions taht can be occupied by 5 consonants

    we have 20 positions avlbl for 5 consonants
    so they can be arranged in 20P5 ways..

    is this method correct ??
    plz help me
    Follow Math Help Forum on Facebook and Google+

  4. #4
    MHF Contributor

    Joined
    Aug 2006
    Posts
    18,649
    Thanks
    1597
    Awards
    1
    Quote Originally Posted by sudhanshu View Post
    ***** I *****A*****E*****
    here * denotes the positions taht can be occupied by 5 consonants
    we have 20 positions avlbl for 5 consonants
    so they can be arranged in 20P5 ways..is this method correct ?
    I this that is well off the mark.

    This is a valid rearrangement: LGEITNRA

    Notice the consonants and vowels remain in relative fixed positions.
    Do you understand?
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Junior Member
    Joined
    Jan 2009
    Posts
    38
    Quote Originally Posted by Plato View Post
    I this that is well off the mark.

    This is a valid rearrangement: LGEITNRA

    Notice the consonants and vowels remain in relative fixed positions.
    Do you understand?
    -----------------------------------------

    Sir,

    in the second part
    we have to keep the relative position of vowels and consonant unchanged

    i have tried it as follows

    C C V V C C C V
    five consonants can be arranged in 5! ways
    three consonants can be arranged in 3! ways
    so the total no. of ways =5!*3!= 120*6 = 720
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Permutations
    Posted in the Discrete Math Forum
    Replies: 2
    Last Post: December 13th 2009, 05:10 AM
  2. Permutations
    Posted in the Discrete Math Forum
    Replies: 9
    Last Post: November 26th 2009, 09:55 PM
  3. Permutations
    Posted in the Discrete Math Forum
    Replies: 4
    Last Post: October 28th 2009, 02:27 PM
  4. permutations
    Posted in the Number Theory Forum
    Replies: 2
    Last Post: May 18th 2009, 01:38 AM
  5. Permutations
    Posted in the Advanced Algebra Forum
    Replies: 1
    Last Post: October 16th 2008, 06:59 PM

Search Tags


/mathhelpforum @mathhelpforum