
Elementary Math Fractions, Percentages, Word Problems, Equations, Inequations, Factorization, Expansion 
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May 11th, 2012, 04:29 AM  #1 
Newbie Joined: Jan 2011 Posts: 10 Thanks: 0  Percentages problem – need help adding percentages please
I need 40% overall to pass my exam. So far I have got: 55% of an exam worth 45% of overall grade, and 75% of an essay worth 10% of overall grade I have one more exam, worth 45% of the overall grade. What is the minimum percentage score I need to achieve to get an overall grade of 40%? I have no idea how to do the math, so any help is great. Thanks 
May 11th, 2012, 09:30 AM  #2 
Senior Member Joined: Jul 2010 From: St. Augustine, FL., U.S.A.'s oldest city Posts: 12,155 Thanks: 463 Math Focus: Calculus/ODEs  Re: Percentages problem – need help adding percentages pleas
Let x represent the minimal score you need. So we have: 0.45·0.55 + 0.10·0.75 + 0.45·x = 0.40 0.2475 + 0.075 + 0.45·x = 0.40 0.3225 + 0.45·x = 0.40 0.45·x = 0.0775 x = 0.17222... Hence, the minimal score is 17 2/9% 
May 11th, 2012, 09:33 AM  #3 
Newbie Joined: Jan 2011 Posts: 10 Thanks: 0  Re: Percentages problem – need help adding percentages pleas
Ah, you're great. Thanks a lot. I've always wondered how to do this. 
May 11th, 2012, 06:56 PM  #4  
Math Team Joined: Oct 2011 From: Ottawa Ontario, Canada Posts: 11,388 Thanks: 730  Re: Percentages problem – need help adding percentages pleas Quote:
 
May 25th, 2012, 02:56 PM  #5 
Math Team Joined: Sep 2007 Posts: 2,409 Thanks: 6  Re: Percentages problem – need help adding percentages pleas
You can just imagine a month old baby, lying in his crib, wondering how to do problems like this!


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