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100 points for $49 worth of Veritas practice GMATs FREE VERITAS PRACTICE GMAT EXAMS Earn 10 Points Per Post Earn 10 Points Per Thanks Earn 10 Points Per Upvote ## The contents of a bag of marbles consist of 9 green... tagged by: BTGmoderatorLU ##### This topic has 2 expert replies and 1 member reply ### Top Member ## The contents of a bag of marbles consist of 9 green... The content of a bag of marbles consist of green 9 marbles and 16 blue marbles. How many blue marbles must be removed so that 60% of the marbles in the bag will be green? (A) 1 (B) 6 (C) 7 (D) 9 (E) 10 The OA is E. Relatively easy question I'm confused with this PS question, I think I have a problem with the concept. Experts, any suggestion about how can I solve it? Thanks in advance. ### GMAT/MBA Expert Elite Legendary Member Joined 23 Jun 2013 Posted: 10197 messages Followed by: 497 members Upvotes: 2867 GMAT Score: 800 Top Reply Hi LUANDATO, We're told that a bag of marbles contains 9 green marbles and 16 blue marbles. We're asked how many blue marbles must be REMOVED so that 60% of the marbles in the bag will be green. We can answer this question by TESTing THE ANSWERS. To start, since we need 60% of the marbles to be green, we therefore need there to be MORE green marbles than blue marbles... and this means that we have to remove at least 8 of the 16 blue marbles. Thus, the correct answer has to be either D or E. Let's TEST Answer E: 10 marbles If we remove 10 blue marbles, then we'll have... 9 green marbles and 6 blue marbles (green)/(total) = 9/15 = 3/5 = 60% This is an exact match for what we were told, so this MUST be the answer. Final Answer: E GMAT assassins aren't born, they're made, Rich _________________ Contact Rich at Rich.C@empowergmat.com ### GMAT/MBA Expert GMAT Instructor Joined 04 Oct 2017 Posted: 551 messages Followed by: 11 members Upvotes: 180 Quote: The content of a bag of marbles consist of green 9 marbles and 16 blue marbles. How many blue marbles must be removed so that 60% of the marbles in the bag will be green? (A) 1 (B) 6 (C) 7 (D) 9 (E) 10 The OA is E. Relatively easy question I'm confused with this PS question, I think I have a problem with the concept. Experts, any suggestion about how can I solve it? Thanks in advance. Hi LUANDATO, Let's take a look at your question. There are 9 green and 16 blue marbles in a bag. Let the 9 green marbles are 60% of a total of 'x' marbles. Then $$x\times60\%=9$$ $$x\times\frac{60}{100}=9$$ $$x=9\times\frac{100}{60}$$ $$x=15$$ It means that if there are a total of 15 marbles in the bag, only then the 9 green marbles are the 60% of the total marbles in the bag. Total marbles = 15 Green marbles = 9 We can now calculate the number of blue marbles in the bag. Blue marbles = 15 - 9 = 6 There were initially 16 blue marbles in the bag, we are asked to find the number of blue marbles that must be removed. Blue marbles that must be removed = 16 - 6 = 10 Therefore, Option E is correct. Hope it helps. I am available if you'd like any follow up. _________________ GMAT Prep From The Economist We offer 70+ point score improvement money back guarantee. Our average student improves 98 points. Free 7-Day Test Prep with Economist GMAT Tutor - Receive free access to the top-rated GMAT prep course including a 1-on-1 strategy session, 2 full-length tests, and 5 ask-a-tutor messages. Get started now. Master | Next Rank: 500 Posts Joined 29 Nov 2017 Posted: 100 messages Upvotes: 14 LUANDATO wrote: The content of a bag of marbles consist of green 9 marbles and 16 blue marbles. How many blue marbles must be removed so that 60% of the marbles in the bag will be green? (A) 1 (B) 6 (C) 7 (D) 9 (E) 10 The OA is E. Relatively easy question I'm confused with this PS question, I think I have a problem with the concept. Experts, any suggestion about how can I solve it? Thanks in advance. If finally x blue marbles are left in the bag then 9 and x must be in the ratio of 60 and 40 That means x/40 = 9/60 or x = 9*40/60=6 Hence 16-6=10 blue marbles must be removed Option E • Magoosh Study with Magoosh GMAT prep Available with Beat the GMAT members only code • 5-Day Free Trial 5-day free, full-access trial TTP Quant Available with Beat the GMAT members only code • Get 300+ Practice Questions 25 Video lessons and 6 Webinars for FREE Available with Beat the GMAT members only code • Free Trial & Practice Exam BEAT THE GMAT EXCLUSIVE Available with Beat the GMAT members only code • Award-winning private GMAT tutoring Register now and save up to$200

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