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My honors Algebra teacher can't teach anything...

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What percent of 75 is 15?

Oct 10, 2017

#1
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What percent of 75 is 15?

Translates to:

$$75\,*\,x\,=15\\ x\%=\frac{15}{75}\\ x=0.2\\ 0.2 = 20\%$$

Tips:

I'll use the same numbers for each example.

Three variants

What percent of 100 is 40?

oldnum * {percent} = newnum

(What percent of the original number [100] gives you the new number [40]?)

100 * ? = 40

? = 40/100

? = 0.4

0.4 --> 40%

What is 40% of 100?

oldnum * percent = {newnum}

([40] percent of the original number [100] results in what number?)

100 * 40% = ?

40% --> 0.4

100 * 0.4 = 40

40% of what is 40?

{oldnum} * percent = newnum

([40] percent of what number gives you the new number [40])?

? * 40% = 40

40% --> 0.4

? * 0.4 = 40

? = 40/0.4

? = 100

*this was hard for me at first, but with practice, you'll get used to the wording of the questions

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Oct 10, 2017
edited by ChowMein  Oct 10, 2017
edited by ChowMein  Oct 10, 2017
#2
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If you are an honours student and you do not already know how to find the percentage of a number then I think you need to drop down several levels and study introductory arithmetic instead.

15/75  *  100% = 20%

Oct 10, 2017