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Old 04-09-2011, 09:08 AM   #1 (permalink)
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Math question.

600/12=50, 600/10=60.

The difference from 10 to 12 is 2, the difference from 50 to 60 is 10.
11 is 50% of the difference between 10 and 12, 55 is 50% of the difference between 50 and 60...

BUT!

600/11=54.54e.

Um?

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Old 04-09-2011, 08:04 PM   #2 (permalink)
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I find it helpful to visualize multiplication and division geometrically. Consider rectanges that are 10*6, 12*5, or 11*5.45 to see why your first intuition isn't correct.
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Old 04-09-2011, 10:40 PM   #3 (permalink)
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Its not my intuition, and I wasnt asking a question... Its pointing out that there are inconsistencies in digit math when using percentages compared to integers.

Intuition would tell you that since 11 is 50% of the diff between 10 and 12, and the respective solutions for ten and twelve were 50 and 60, the solution for 11 should be 50% of the difference. However, average would-be mathematicians haven't accounted for the scaled increase when using the percentile as an intuitive route to check a solution.

600/11 is, in fact, 54.54e, just slightly less than 50% of the difference between the solution for 600/10 & 600/12, even though 11 is exactly 50% of the difference between 10 and 12.
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Old 04-10-2011, 01:16 PM   #4 (permalink)
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Math questions are answered here:

http://www.khanacademy.org/

Specifically on percentages:

Khan Academy
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Old 04-14-2011, 08:44 AM   #5 (permalink)
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Christ, if you were to divide different numbers by the same denominator, then the function would be linear, and proportions would work. But when you divide the same numerator by different denominators the function is now rational, which is governed by its own laws. Percentiles and averages become less intuitive.
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Old 04-14-2011, 12:37 PM   #6 (permalink)
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Old 04-14-2011, 02:18 PM   #7 (permalink)
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Odin -

Quote:
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Ok, that answers my question.

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Old 04-14-2011, 03:39 PM   #8 (permalink)
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C, the answer is always "C"
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Old 04-14-2011, 05:55 PM   #9 (permalink)
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Christ -

I made this plot of denominator increments of 0.1 and the result :



The red line is "as if" the result was linear.

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Old 04-14-2011, 06:43 PM   #10 (permalink)
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That illustrates the point, Carlos. Thank you.

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