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Math Help - Pemutation problem

  1. #1
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    Pemutation problem

    Hello,

    m not sure if this is the right section to post permutation problem, but anyways please help me out with the following

    In how many ways can 10 soldiers stand in 2 rows such that there are 5 soldiers in each row?

    Is the answer 7257600 or 7257600/2 ?

    Puneet
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  2. #2
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    Quote Originally Posted by skyskiers View Post
    In how many ways can 10 soldiers stand in 2 rows such that there are 5 soldiers in each row?
    It is just 10!=3628800
    Take any line of ten and divide it into two rows.
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  3. #3
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    Quote Originally Posted by Plato View Post
    It is just 10!=3628800
    Take any line of ten and divide it into two rows.

    Yes, you are rig5!ht..it should be 10! , bu was just confused as the text bok says it to be 2*10!

    Their logic

    10c5 * 5! * 5! * 2

    Wouldnt we first divide the line in to groups(equal) of 5 and 5 and the multiply it by 2? As in

    10!/(5!)^2 * ( 5!) * (5!) *2 = 10!
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