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Math Help - I Find With My Little Mind

  1. #1
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    I Find With My Little Mind

    I'm thinking of a number between 1-100...

    1/5 and 1/3 of the number are both integers.
    there are 9 other integers in between 1/5 and 1/3 (excluding them).

    (Easy question for most of you)
    Last edited by Obsidantion; August 17th 2008 at 11:23 AM.
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  2. #2
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    Quote Originally Posted by Obsidantion View Post
    I'm thinking of a number between 1-100...

    1/5 and 1/3 are both integers.
    there are 9 other integers in between 1/5 and 1/3 (excluding them).

    (Easy question for most of you)
    By definition a fraction is not an integer...
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  3. #3
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    I think the OP means 1/3 and 1/5 of the integer.

    Well, set up your equation. Let n be this number you're trying to find. So, the difference between \frac{1}{3}n and \frac{1}{5}n should equal to 10 (you want 9 integers between (1/3)n and (1/5)n but when you subtract 2 numbers, you include the number you start with which adds 1 to the number of integers in between them. For example, if you want the number of integers between 6 and 3, it's 2. But 6 - 3 = 3 (one more than 2) because you include 6 ).

    So you have your equation: \frac{1}{3}n - \frac{1}{5}n = 10
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  4. #4
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    n(2/15) = 10

    2n = 150

    n = 75
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  5. #5
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    Quote Originally Posted by Sweed View Post
    n(2/15) = 10

    2n = 150

    n = 75
    Right again!
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