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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 A bar of gold with dimensions 12 inches by 18 inches by 15 This topic has 4 expert replies and 4 member replies Top Member A bar of gold with dimensions 12 inches by 18 inches by 15 A bar of gold with dimensions 12 inches by 18 inches by 15 inches is melted down and re-formed into a bar of different dimensions. All of the following are possible dimensions of the new gold bar EXCEPT: A. 10 inches by 15 inches by 22 inches B. 12 inches by 10 inches by 27 inches C. 6 inches by 18 inches by 30 inches D.24 inches by 27 inches by 5 inches E. 9 inches by 24 inches by 15 inches Can some experts find the best Option? OA A GMAT/MBA Expert GMAT Instructor Joined 25 Apr 2015 Posted: 2950 messages Followed by: 19 members Upvotes: 43 Top Reply lheiannie07 wrote: A bar of gold with dimensions 12 inches by 18 inches by 15 inches is melted down and re-formed into a bar of different dimensions. All of the following are possible dimensions of the new gold bar EXCEPT: A. 10 inches by 15 inches by 22 inches B. 12 inches by 10 inches by 27 inches C. 6 inches by 18 inches by 30 inches D.24 inches by 27 inches by 5 inches E. 9 inches by 24 inches by 15 inches The key to solving this problem is to notice that when we melt and re-form the gold bar, the volume of the re-formed gold bar will be the same as the original gold bar. Therefore, we must compare the volumes of the answer choices with the volume of the given gold bar. A helpful way to solve this problem is to recognize that we can factor the answer choices to determine any difference between the factors of the dimensions in those choices and the given dimensions of 12 by 18 by 15. The original barâ€™s dimensions factor to 2^3 x 3^4 x 5^1. In scanning the answer choices, we see that answer choice A has dimensions of 10 by 15 by 22. Thus, those dimensions contain a factor of 11. Since the original dimensions of 12 by 18 by 15 DO NOT contain a factor of 11, answer choice A is correct. Answer:A _________________ Scott Woodbury-Stewart Founder and CEO scott@targettestprep.com See why Target Test Prep is rated 5 out of 5 stars on BEAT the GMAT. Read our reviews GMAT/MBA Expert GMAT Instructor Joined 22 Aug 2016 Posted: 2008 messages Followed by: 31 members Upvotes: 470 Top Reply lheiannie07 wrote: A bar of gold with dimensions 12 inches by 18 inches by 15 inches is melted down and re-formed into a bar of different dimensions. All of the following are possible dimensions of the new gold bar EXCEPT: A. 10 inches by 15 inches by 22 inches B. 12 inches by 10 inches by 27 inches C. 6 inches by 18 inches by 30 inches D.24 inches by 27 inches by 5 inches E. 9 inches by 24 inches by 15 inches Can some experts find the best Option? OA A The volume of the reformed bar must be equal to the original bar. Volume of the original bar = 12 * 18 * 15; let's factorize it into prime factors. 12 * 18 * 15 = (2^2 * 3) * (2 * 3^2) * (3 * 5) = 2^3 * 3^4 * 5 The option that does not have prime factors of their volume = 2^3 * 3^4 * 5 is the correct answer. We see that one of the dimensions of option A is 22 inches; this will give a prime factor 11, which is not there is the volume of the original bar, thus, it is the correct answer. The correct answer: A Hope this helps! -Jay _________________ Manhattan Review GMAT Prep Locations: New York | Singapore | Doha | Lausanne | and many more... Schedule your free consultation with an experienced GMAT Prep Advisor! Click here. GMAT/MBA Expert GMAT Instructor Joined 04 Oct 2017 Posted: 551 messages Followed by: 11 members Upvotes: 180 Quote: A bar of gold with dimensions 12 inches by 18 inches by 15 inches is melted down and re-formed into a bar of different dimensions. All of the following are possible dimensions of the new gold bar EXCEPT: A. 10 inches by 15 inches by 22 inches B. 12 inches by 10 inches by 27 inches C. 6 inches by 18 inches by 30 inches D.24 inches by 27 inches by 5 inches E. 9 inches by 24 inches by 15 inches Can some experts find the best Option? OA A Hi lheiannie07, Let's take a look at your question. Volume of the bar of gold can be represented as: $$=12\times18\times15inches^3$$ Write it as a product of prime factors. $$=2\times2\times3\times2\times3\times3\times3\times5\ inches^3$$ $$=2^3\times3^4\times5\ inches^3$$ Let's now write the given options as a product of their prime factors and check which one of these is different from the volume of gold bar. Option A: 10 inches by 15 inches by 22 inches $$=10\times15\times22\ inches^3$$ $$=2\times5\times3\times5\times2\times11\ inches^3$$ $$=2^2\times3\times5^2\times11\ inches^3$$ This does not represent the volume of the gold bar as it is different from $$2^3\times3^4\times5\ inches^3$$ . Therefore, Option A 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. GMAT/MBA Expert Elite Legendary Member Joined 23 Jun 2013 Posted: 10197 messages Followed by: 497 members Upvotes: 2867 GMAT Score: 800 Hi lheiannie07, We're told that a bar of gold with dimensions 12 inches by 18 inches by 15 inches is melted down and re-formed into a bar of different dimensions. We're also told that 4 of the 5 answers choices ARE possible dimensions of the new gold bar. We're asked to find the one that's NOT. We can actually use the answer choices 'against' the prompt and TEST THE ANSWERS. To start, this question involves the VOLUME of the gold bar - although we don't actually have to calculate the entire volume. Notice the dimensions (12 by 18 by 15)... Answer A: 10 by 15 by 22 This Answer includes a 15 (the same as the original bar had), so we can 'ignore' those 15s and focus on what's left: (10 by 22) vs. (12 by 18).... (10 by 22) = 220 (12 by 18) = 216 These are NOT the same results. The volume of Answer A would be BIGGER than the volume of the original bar, so this result is NOT possible and Answer A must be the answer. Final Answer: A GMAT assassins aren't born, they're made, Rich _________________ Contact Rich at Rich.C@empowergmat.com Top Member Moderator Joined 07 Sep 2017 Posted: 3159 messages Followed by: 8 members EconomistGMATTutor wrote: Quote: A bar of gold with dimensions 12 inches by 18 inches by 15 inches is melted down and re-formed into a bar of different dimensions. All of the following are possible dimensions of the new gold bar EXCEPT: A. 10 inches by 15 inches by 22 inches B. 12 inches by 10 inches by 27 inches C. 6 inches by 18 inches by 30 inches D.24 inches by 27 inches by 5 inches E. 9 inches by 24 inches by 15 inches Can some experts find the best Option? OA A Hi lheiannie07, Let's take a look at your question. Volume of the bar of gold can be represented as: $$=12\times18\times15inches^3$$ Write it as a product of prime factors. $$=2\times2\times3\times2\times3\times3\times3\times5\ inches^3$$ $$=2^3\times3^4\times5\ inches^3$$ Let's now write the given options as a product of their prime factors and check which one of these is different from the volume of gold bar. Option A: 10 inches by 15 inches by 22 inches $$=10\times15\times22\ inches^3$$ $$=2\times5\times3\times5\times2\times11\ inches^3$$ $$=2^2\times3\times5^2\times11\ inches^3$$ This does not represent the volume of the gold bar as it is different from $$2^3\times3^4\times5\ inches^3$$ . Therefore, Option A is correct. Hope it helps. I am available if you'd like any follow up. Thanks a lot! Top Member Moderator Joined 07 Sep 2017 Posted: 3159 messages Followed by: 8 members Jay@ManhattanReview wrote: lheiannie07 wrote: A bar of gold with dimensions 12 inches by 18 inches by 15 inches is melted down and re-formed into a bar of different dimensions. All of the following are possible dimensions of the new gold bar EXCEPT: A. 10 inches by 15 inches by 22 inches B. 12 inches by 10 inches by 27 inches C. 6 inches by 18 inches by 30 inches D.24 inches by 27 inches by 5 inches E. 9 inches by 24 inches by 15 inches Can some experts find the best Option? OA A The volume of the reformed bar must be equal to the original bar. Volume of the original bar = 12 * 18 * 15; let's factorize it into prime factors. 12 * 18 * 15 = (2^2 * 3) * (2 * 3^2) * (3 * 5) = 2^3 * 3^4 * 5 The option that does not have prime factors of their volume = 2^3 * 3^4 * 5 is the correct answer. We see that one of the dimensions of option A is 22 inches; this will give a prime factor 11, which is not there is the volume of the original bar, thus, it is the correct answer. The correct answer: A Hope this helps! -Jay _________________ Manhattan Review GMAT Prep Locations: New York | Singapore | Doha | Lausanne | and many more... Schedule your free consultation with an experienced GMAT Prep Advisor! Click here. Thanks a lot! Top Member Moderator Joined 07 Sep 2017 Posted: 3159 messages Followed by: 8 members Rich.C@EMPOWERgmat.com wrote: Hi lheiannie07, We're told that a bar of gold with dimensions 12 inches by 18 inches by 15 inches is melted down and re-formed into a bar of different dimensions. We're also told that 4 of the 5 answers choices ARE possible dimensions of the new gold bar. We're asked to find the one that's NOT. We can actually use the answer choices 'against' the prompt and TEST THE ANSWERS. To start, this question involves the VOLUME of the gold bar - although we don't actually have to calculate the entire volume. Notice the dimensions (12 by 18 by 15)... Answer A: 10 by 15 by 22 This Answer includes a 15 (the same as the original bar had), so we can 'ignore' those 15s and focus on what's left: (10 by 22) vs. (12 by 18).... (10 by 22) = 220 (12 by 18) = 216 These are NOT the same results. The volume of Answer A would be BIGGER than the volume of the original bar, so this result is NOT possible and Answer A must be the answer. Final Answer: A GMAT assassins aren't born, they're made, Rich Thanks a lot! Top Member Master | Next Rank: 500 Posts Joined 15 Oct 2009 Posted: 330 messages Upvotes: 27 lheiannie07 wrote: A bar of gold with dimensions 12 inches by 18 inches by 15 inches is melted down and re-formed into a bar of different dimensions. All of the following are possible dimensions of the new gold bar EXCEPT: A. 10 inches by 15 inches by 22 inches B. 12 inches by 10 inches by 27 inches C. 6 inches by 18 inches by 30 inches D.24 inches by 27 inches by 5 inches E. 9 inches by 24 inches by 15 inches Can some experts find the best Option? OA A Following on based on the factorization, you can see there is only 5 represented. Inspecting the choices indicates that all the choices except A have just one 5 as a factor and that A has two factors of 5 • 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 • 5 Day FREE Trial Study Smarter, Not Harder 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 • Free Veritas GMAT Class Experience Lesson 1 Live Free Available with Beat the GMAT members only code • Award-winning private GMAT tutoring Register now and save up to$200

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