Anonymous
Anonymous asked in Science & MathematicsMathematics · 1 decade ago

How many ways can 1 2 3 5 5 8 be arranged and how many of these numbers could be divided by 15?

just as the title asks how many ways can 1 2 3 5 5 8 be arranged and how many numbers can be divided by 15?

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  • 1 decade ago
    Best answer

    Hi,

    In order to be divisible by 15, a number must end in either 5 or 0, and the sum of all its digits must be divisible by 3. Since 0 was not included in the numbers to be arranged, then 5 must be in the last position. That leaves the other 5 digits to be arranged in 5! ways. This makes 120 distinguishable arrangements of those 6 digits.

    120 ways <==ANSWER

    I hope that helps!! :-)

  • 1 decade ago

    To figure out how many ways it can be arranged, it's just 6!. However, since 5 appears twice, it is 6!/2! or 360.

    In order for it to be divisible by 15, the last digit has to equal 5 (since 1+2+3+5+5+8=24, and that's already divisible by 3)

    From the rest of the digits, it's just 5! or 120.

  • M3
    Lv 7
    1 decade ago

    a) the number can be arranged in 6!/2! = 360 ways

    b) all numbers ending with 5 will also be divisible by 15

    so they will number (2/6)*360 = 120

  • 1 decade ago

    I think they can be arranged 6! different ways.

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  • 1 decade ago

    well the answer to the first question is.....first you must use a permutation or a combinattion(sorry i forgot which ones which)....which is where you do 1*2*3*4*5*6 because there are six numbers... the second one....ya gotta figure it out!

    Source(s): my brain!!!
  • Anonymous
    1 decade ago

    all i know is that they can be arranged in 36 ways.

    i think;;

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