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Math Help - How to find out what a fraction is as a percentage?

  1. #1
    Junior Member Subliminalmessage's Avatar
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    How to find out what a fraction is as a percentage?

    I've got six questions I've picked out of many I can't seem to get exactly right.

    1/12 as a percentage = 8.4% (correct answers is 8.3%)
    1/8 = 12.4% (12.5%)
    1/16 = 6.4% (6.25%)
    2/3 = 66.2% (66.6%)
    6/16 = 36.24% (37.5%)
    5/8 = 32.0% (62.5%)

    So, the way I worked these out is as following, I'll show you one example of how I got these incorrect answers.

    2/3, 3 divided by 100, so 3 goes into 10, 3 times remainder 1 put the 1 ontop of the second 0 and it becomes 10 and 3 goes into 10, 3 times remainder 1.

    So I've got 33.1 now I times 33.1 with the top number of the fraction which is 2, 33.1 x 2 = 66.2%?

    Any idea where I'm going wrong here? Thanks.
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  2. #2
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    Re: How to find out what a fraction is as a percentage?

    Quote Originally Posted by Subliminalmessage View Post
    I've got six questions I've picked out of many I can't seem to get exactly right.

    1/12 as a percentage = 8.4% (correct answers is 8.3%)
    1/8 = 12.4% (12.5%)
    1/16 = 6.4% (6.25%)
    2/3 = 66.2% (66.6%)
    6/16 = 36.24% (37.5%)
    5/8 = 32.0% (62.5%)

    So, the way I worked these out is as following, I'll show you one example of how I got these incorrect answers.

    2/3, 3 divided by 100, so 3 goes into 10, 3 times remainder 1 put the 1 ontop of the second 0 and it becomes 10 and 3 goes into 10, 3 times remainder 1.

    So I've got 33.1 now I times 33.1 with the top number of the fraction which is 2, 33.1 x 2 = 66.2%?

    Any idea where I'm going wrong here? Thanks.
    a/b as a percentage= (a divided by b)*100
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  3. #3
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    Re: How to find out what a fraction is as a percentage?

    \displaystyle \frac{100}{3}=33 remainder \displaystyle 1,

    but that is \displaystyle 33+\frac{1}{3}=33 + 0.333...=33.333..., not 33.1
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  4. #4
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    Re: How to find out what a fraction is as a percentage?

    Quote Originally Posted by Subliminalmessage View Post
    I've got six questions I've picked out of many I can't seem to get exactly right.

    1/12 as a percentage = 8.4% (correct answers is 8.3%)
    1/8 = 12.4% (12.5%)
    1/16 = 6.4% (6.25%)
    2/3 = 66.2% (66.6%)
    6/16 = 36.24% (37.5%)
    5/8 = 32.0% (62.5%)

    So, the way I worked these out is as following, I'll show you one example of how I got these incorrect answers.

    2/3, 3 divided by 100
    You mean 100 divided by 3

    , so 3 goes into 10, 3 times remainder 1 put the 1 ontop of the second 0 and it becomes 10 and 3 goes into 10, 3 times remainder 1.

    So I've got 33.1 now I times 33.1 with the top number of the fraction which is 2, 33.1 x 2 = 66.2%?
    Yes. Another way to do this would be to divide 200 by 3, and yet another way is to divide 2 by 3, then multiply by 3.

    Any idea where I'm going wrong here? Thanks.
    For that example, at least, you are not doing anything wrong.
    \frac{a}{b}, converted to a percent, can be thought of as [tex]\frac{100}{b}[/itex], multiplied by a, or \frac{100a}{b}, or \frac{a}{b} multilied by 100. In any case, you divide a by b and multiply by 100. Because multiplication (and division) are "commutative" the order in which you do that doesn't matter.

    1/12 as a percentage = 8.4% (correct answers is 8.3%)
    12 divides into 100 8 times with remainder 4. 12 divides into 40 3 times with remainder 4 again. If you keep on you will repeatedly get "3 times with remainder 3. 12 divides into 100 8.333333333333333333333333333... which, rounded to tenths place, is 8.3%. The fact that the last remainder was "4" does NOT mean the last digit is 4!

    [quote]1/8 = 12.4% (12.5%)[quote]
    8 divides into 100 12 times with remainder 4. Bringing down a "0", 8 divides into 40 5 times: 8 divides into 100 12.5 times. Again, the fact that the remaider is 4 does NOT mean that the digit is 4, it means it is 4/8= 1/2= .5.

    1/16 = 6.4% (6.25%)
    16 divides into 100 6 times with remainder 4. I think I see a pattern here! The remainder is NOT the last digit. 4/16= 1/4= .25.
    You continue these. Remember, the "last" remaider is NOT a digit in the quotient. Your difficulty here has nothing to do with "percents"- it is with long division.

    [quote]2/3 = 66.2% (66.6%)
    6/16 = 36.24% (37.5%)
    5/8 = 32.0% (62.5%)
    Last edited by HallsofIvy; July 1st 2012 at 07:35 PM.
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