My Math Forum 72 correct equals 75%. Total being...?

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 June 1st, 2015, 06:39 AM #1 Member   Joined: May 2015 From: U.S.A. Posts: 45 Thanks: 0 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?
 June 1st, 2015, 06:46 AM #2 Banned Camp   Joined: May 2015 From: Casablanca Posts: 36 Thanks: 7 S=$(72*100)/75=96$ This question is related to "Ratios and proportions" Thanks from Rexan Last edited by Assayid; June 1st, 2015 at 06:52 AM.
June 1st, 2015, 09:18 AM   #3
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Quote:
 Originally Posted by Rexan 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.

$\displaystyle 75 \% \ \ of \ \ x \ =\ 72 \\\;\\ \dfrac{75}{100}\cdot \ x =72 \\\;\\ x\ =\ 72\cdot\dfrac{100}{75} = 72\cdot \dfrac{4}{3}\ =\ 24\cdot 4= 96 .$

June 1st, 2015, 03:28 PM   #4
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Quote:
 Originally Posted by Assayid S=$(72*100)/75=96$ This question is related to "Ratios and proportions"
Quote:
 Originally Posted by aurel5 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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