Elementary Math Fractions, Percentages, Word Problems, Equations, Inequations, Factorization, Expansion

 May 11th, 2012, 03:29 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, 08:30 AM #2 Senior Member     Joined: Jul 2010 From: St. Augustine, FL., U.S.A.'s oldest city Posts: 12,204 Thanks: 511 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, 08:33 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, 05:56 PM   #4
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Re: Percentages problem – need help adding percentages pleas

Quote:
 Originally Posted by BellEnd I've always wondered how to do this.
always ?

 May 25th, 2012, 01:56 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!