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In how many ways can 5 differently colored marbles be arranged in a row?

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in how many ways can 5 differently colored marbles be arranged in a row?

A) 50 , B) 1/5! , C) 5! , D) 250 .

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  1. C)5!


  2. C) 5! is the answer

    because 5! = 5 * 4 * 3 * 2 * 1

    There are 5 spaces for the marbles.

    The 1st marble can go in any of the 5 spaces so the number of combinations is 5.

    The 2nd marble can only go in 4 of the 5 since 1 space is being occupied by the 1st marble... so the number of combinations is multiplied by 4.

    The 3nd marble can only go in 3 of the 5 since 2 spaces are being occupied by the 1st and 2nd marbles... so the number of combinations is multiplied by 3.

    so on and so forth.....

  3. The first marble can be one of 5 colours.

    For each of these 5 colours, the second marble can then be one of 4 colours.

    For each of these 5x4 combinations, the third marble can be one of 3 remaining colours.

    For each of these 5x4x3 combinations, the fourth marble can be one of 2 remaining colours.

    For each of these 5x4x3x2 combinations, the last marble can only be the remaining colour.

    Total combinations: 5x4x3x2x1 = 5!  = 120

  4. It helps if you draw 5 boxes and put the number of choices in each box and then multiply

    First box: You have 5 choices, put in number 5

    Second box: having already used up 1 marble (in the first box) there are now only 4 options left, put 4 in second box...and so on

    5 x 4 x 3 x 2 x 1 = 120 = 5! ways

  5. c.5

    because you can only simultaneously arrange it and does not affect the other marble

  6. To put the first marble, you have 5 to choose from.

    To put the next one you have 4 to choose from; you have already used one.

    And so on.

    5 x 4 x 3 x 2 x 1

    5!

    C

    See?

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