• NEW! FREE Beat The GMAT Quizzes
Hundreds of Questions Highly Detailed Reporting Expert Explanations
• 7 CATs FREE!
If you earn 100 Forum Points

Engage in the Beat The GMAT forums to earn
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 variables a and b are non-zero integers... tagged by: BTGmoderatorLU ##### This topic has 2 expert replies and 0 member replies ### Top Member ## The variables a and b are non-zero integers... The variables a and b are non-zero integers. If a=2b^3/c, what happens to c when a is halved and b is doubled? A. c is not changed B. c is halved C. c is doubled D. c is multiplied by 4 E. c is multiplied by 16 The OA is E. I'm confused with this PS question, what should I do to solve it? Isolate c? I'm not sure. Experts, any suggestion? 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 Vincen, To start, there's a slight 'typo' in the equation - I've noted the correct in my explanation: We're told that the variables A and B are non-zero integers and that A = ((2B)^3)/C. We're asked what happens to A when A is halved and B is doubled. This question can be solved by TESTing VALUES. IF... B = 1 and C = 1 A = (8)/1 = 8 By halving A (A becomes 4) and doubling B (B becomes 2), we get.... 4 = (64)/C 4C = 64 C = 16 Thus, C = 1 becomes C = 16, so C becomes multiplied by 16. 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 Top Reply Hello LUANDATO. Let's see your question. We have that $$a=\frac{2b^3}{c},\ \ \ \text{then}\ \ c=\frac{2b^3}{a}.$$ Now, if we write "a/2" instead of "a" and "2b" instead of "b", we will get: $$c=\frac{2\left(2b\right)^3}{\frac{a}{2}}=\frac{2\cdot8b^3}{\frac{a}{2}}=\frac{32b^3}{a}=16\cdot\frac{2b^3}{a}=16\cdot c.$$ So, the correct answer is E. I hope this explanation may help you. I'm available if you'd like a follow-up. Regards. _________________ 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. • Award-winning private GMAT tutoring Register now and save up to$200

Available with Beat the GMAT members only code

• Free Trial & Practice Exam
BEAT THE GMAT EXCLUSIVE

Available with Beat the GMAT members only code

• Free Practice Test & Review
How would you score if you took the GMAT

Available with Beat the GMAT members only code

• FREE GMAT Exam
Know how you'd score today for \$0

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 Veritas GMAT Class
Experience Lesson 1 Live Free

Available with Beat the GMAT members only code

• 5 Day FREE Trial
Study Smarter, Not Harder

Available with Beat the GMAT members only code

• Magoosh
Study with Magoosh GMAT prep

Available with Beat the GMAT members only code

• 1 Hour Free
BEAT THE GMAT EXCLUSIVE

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

### Top First Responders*

1 Ian Stewart 41 first replies
2 Brent@GMATPrepNow 40 first replies
3 Scott@TargetTestPrep 39 first replies
4 Jay@ManhattanReview 32 first replies
5 GMATGuruNY 26 first replies
* Only counts replies to topics started in last 30 days
See More Top Beat The GMAT Members

### Most Active Experts

1 Scott@TargetTestPrep

Target Test Prep

159 posts
2 Max@Math Revolution

Math Revolution

92 posts
3 Brent@GMATPrepNow

GMAT Prep Now Teacher

60 posts
4 Ian Stewart

GMATiX Teacher

50 posts
5 GMATGuruNY

The Princeton Review Teacher

37 posts
See More Top Beat The GMAT Experts