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June 1st, 2015, 06:39 AM   #1
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72 correct equals 75%. Total being...?

A student who correctly answered 72 questions received a score of 75%. How many questions were on the test?

I didn't know how to begin this one, but the only way I can come up with for solving it is 1.25 x 75, with the .25 being the percentage left to get 100%. I know the reasoning doesn't pan out (25% of 75 won't be the same as 25% of the test's total questions), but I can't figure out what else to do.

Also, what would this sort of question be called so I can look up more?
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June 1st, 2015, 06:46 AM   #2
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S=$(72*100)/75=96$
This question is related to "Ratios and proportions"
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Last edited by Assayid; June 1st, 2015 at 06:52 AM.
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June 1st, 2015, 09:18 AM   #3
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Quote:
Originally Posted by Rexan View Post
A student who correctly answered 72 questions received a score of 75%. How many questions were on the test?
Be $\displaystyle x$ the total number of questions.

$\displaystyle 75 \% \ \ of \ \ x \ =\ 72
\\\;\\
\dfrac{75}{100}\cdot \ x =72
\\\;\\
x\ =\ 72\cdot\dfrac{100}{75} = 72\cdot \dfrac{4}{3}\ =\ 24\cdot 4= 96 .$
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June 1st, 2015, 03:28 PM   #4
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Quote:
Originally Posted by Assayid View Post
S=$(72*100)/75=96$
This question is related to "Ratios and proportions"
Quote:
Originally Posted by aurel5 View Post
Be $\displaystyle x$ the total number of questions.

$\displaystyle 75 \% \ \ of \ \ x \ =\ 72
\\\;\\
\dfrac{75}{100}\cdot \ x =72
\\\;\\
x\ =\ 72\cdot\dfrac{100}{75} = 72\cdot \dfrac{4}{3}\ =\ 24\cdot 4= 96 .$
Thanks, both of you! You helped me figure it out and I was able to find other great pages (especially this one) to help out and give some practice questions.
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