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Math Help - Permutations and combinations

  1. #1
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    Permutations and combinations

    1. An ambulance has nine members available for duty.
    i. In how many ways can the nine members be arranged in a straight line?
    ii. In how many ways can two members be selected from them in order to visit an accident site? (Hint: Order of selection is not important.)
    iii. Suppose order of selection is important, in how many ways can the two be selected from the nine members?


    what is the first step

    not so good with permitations
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  2. #2
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    got out the first 1
    the answer is 362880

    can someone help me with the second
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  3. #3
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    For 1.ii, order is not important, so use combinations. For 1.iii, order is important, so use permutations.
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