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 January 12th, 2017, 04:10 PM #1 Member   Joined: Mar 2016 From: NJ Posts: 48 Thanks: 2 Finding the total number if I have a % Hi, I know it's on Khan Academy but not sure what the specific word is for my question to find it. If you have a problem where you know 111 is 32% of a number, how do you find the number? (I don't care about that specific number, but in general how you solve problems like that.) I know I've done it before and it was a lot easier than I thought but for some reason it escapes me. Thanks. Last edited by blimper; January 12th, 2017 at 04:11 PM. Reason: change example
 January 12th, 2017, 04:27 PM #2 Senior Member     Joined: Sep 2015 From: USA Posts: 2,553 Thanks: 1403 $a = p \% \text{ of } b$ $a = \dfrac{p}{100}b$ $\dfrac{100 a}{p} = b$ $111 = 32 \% \text{ of } b$ $b = \dfrac{11100}{32} = 346.875$
 January 12th, 2017, 05:08 PM #3 Member   Joined: Mar 2016 From: NJ Posts: 48 Thanks: 2 Thank you!
 January 12th, 2017, 05:22 PM #4 Math Team     Joined: Jul 2011 From: Texas Posts: 3,016 Thanks: 1600 $111$ $\color{red}{is}$ $\color{blue}{\text{32%}}$ of a $\color{green}{number}$ $111$ $\color{red}{=}$ $\color{blue}{0.32}(\color{green}{number})$ $\dfrac{111}{\color{blue}{0.32}} \color{red}{=} \color{green}{number}$ Thanks from Benit13
January 13th, 2017, 07:39 AM   #5
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Quote:
 Originally Posted by blimper I know it's on Khan Academy but not sure what the specific word is for my question to find it.
A Google video (or youtube) search for Percent word problem finds KA's laboriously worked example (numbered 5) and others. Note that such videos tend to work a particular example (or examples) without explaining the general mathematical principles involved. Also, they tend not to tell you how to verify that your answer is correct, and don't tell you the commonest mistakes that are made when doing such problems.

January 13th, 2017, 12:50 PM   #6
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Quote:
 Originally Posted by blimper If you have a problem where you know 111 is 32% of a number, how do you find the number?
32% of "that number" WAS calculated:
n * .32 = 111
So calculating n is a no-brainer, right?

 January 23rd, 2017, 01:58 AM #7 Member   Joined: Sep 2016 From: India Posts: 88 Thanks: 30 It's a simple problem, let the $x$ and make proportion. $111$ is $32\%$ of $x$ $\dfrac{111}{x}=\dfrac{32}{100}$ $32x=11100$ $x=\dfrac{11100}{32}$ $x=346.875$
January 24th, 2017, 02:40 AM   #8
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Quote:
 Originally Posted by blimper Hi, I know it's on Khan Academy but not sure what the specific word is for my question to find it. If you have a problem where you know 111 is 32% of a number, how do you find the number? (I don't care about that specific number, but in general how you solve problems like that.) I know I've done it before and it was a lot easier than I thought but for some reason it escapes me. Thanks.
The answer is 355. You multiply 111 by 32 % then move the decimal over one slot when you get 35.52

 January 24th, 2017, 03:31 AM #9 Global Moderator   Joined: Dec 2006 Posts: 20,969 Thanks: 2222 It's necessary to divide (not multiply) 111 by .32, as already explained.
January 25th, 2017, 06:21 PM   #10
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Quote:
 Originally Posted by blimper Hi, I know it's on Khan Academy but not sure what the specific word is for my question to find it. If you have a problem where you know 111 is 32% of a number, how do you find the number? (I don't care about that specific number, but in general how you solve problems like that.) I know I've done it before and it was a lot easier than I thought but for some reason it escapes me. Thanks.
Divide by 32, then multiply by 100. I do think that memorizing formulas are harder than doing it automatically.

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