• 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 A garage has a stock of side mirrors. The ratio of right tagged by: swerve This topic has 2 expert replies and 0 member replies Top Member A garage has a stock of side mirrors. The ratio of right Timer 00:00 Your Answer A B C D E Global Stats Difficult A garage has a stock of side mirrors. The ratio of right side mirrors to left side mirrors is 5:3. Iris, a garage worker, attaches pairs of left and right mirrors with an adhesive tape until no more pairs can be made. If 30 right mirrors are left unpaired, how many left and right mirrors are there in the stock? A. 240 B. 120 C. 80 D. 75 E. 48 The OA is B. Source: Economist GMAT GMAT/MBA Expert GMAT Instructor Joined 09 Oct 2010 Posted: 1434 messages Followed by: 32 members Upvotes: 59 swerve wrote: A garage has a stock of side mirrors. The ratio of right side mirrors to left side mirrors is 5:3. Iris, a garage worker, attaches pairs of left and right mirrors with an adhesive tape until no more pairs can be made. If 30 right mirrors are left unpaired, how many left and right mirrors are there in the stock? A. 240 B. 120 C. 80 D. 75 E. 48 Source: Economist GMAT Excellent opportunity to use the k technique : $$\left\{ \matrix{ {\rm{Right}} = 5k \hfill \cr {\rm{Left}} = 3k \hfill \cr} \right.\,\,\,\,\,\,\,\,\,\left( {k \ge 1\,\,{\mathop{\rm int}} \,\,\left( * \right)} \right)\,\,\,\,\,\,\,\,\,$$ $$\left( * \right)\,\,\,k = 2 \cdot \left( {3k} \right) - 5k = 2 \cdot {\mathop{\rm int}} - {\mathop{\rm int}} = {\mathop{\rm int}}$$ $$? = 8k\,\,\,\,\,\,\,\,\,\,\,$$ $$\left\{ \matrix{ \,\,3k\,\,{\rm{pairings}} \hfill \cr \,\,30 = \left( {5k - 3k} \right) = 2k\,\,{\rm{Right}}\,{\rm{unpaired}}\,\,\,\,\,\,\, \Rightarrow \,\,\,\,\,\,\,\,\,2k = 30\,\,\,\,\,\,\,\mathop \Rightarrow \limits_{{\rm{FOCUS}}\,!}^{ \cdot \,\,4} \,\,\,\,\,\,\,? = 8k = 4 \cdot 30 = 120 \hfill \cr} \right.\,\,\,\,\,\,$$ This solution follows the notations and rationale taught in the GMATH method. Regards, Fabio. _________________ Fabio Skilnik :: GMATH method creator ( Math for the GMAT) English-speakers :: https://www.gmath.net Portuguese-speakers :: https://www.gmath.com.br GMAT/MBA Expert GMAT Instructor Joined 25 Apr 2015 Posted: 2224 messages Followed by: 17 members Upvotes: 43 swerve wrote: A garage has a stock of side mirrors. The ratio of right side mirrors to left side mirrors is 5:3. Iris, a garage worker, attaches pairs of left and right mirrors with an adhesive tape until no more pairs can be made. If 30 right mirrors are left unpaired, how many left and right mirrors are there in the stock? A. 240 B. 120 C. 80 D. 75 E. 48 We can let 5x = the number of right side mirrors and 3x = the number of left side mirrors. We can create the equation: 5x - 3x = 30 2x = 30 x = 15 Therefore, there are a total of 5(15) + 3(15) = 120 mirrors. Answer: B _________________ Scott Woodbury-Stewart Founder and CEO • 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 • Free Veritas GMAT Class Experience Lesson 1 Live Free 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

• Award-winning private GMAT tutoring
Register now and save up to \$200

Available with Beat the GMAT members only code

• 5 Day FREE Trial
Study Smarter, Not Harder

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

• Magoosh
Study with Magoosh GMAT prep

Available with Beat the GMAT members only code

Top First Responders*

1 GMATGuruNY 58 first replies
2 Brent@GMATPrepNow 44 first replies
3 Jay@ManhattanReview 41 first replies
4 Ian Stewart 29 first replies
5 ceilidh.erickson 17 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

212 posts
2 fskilnik@GMATH

GMATH Teacher

128 posts
3 Max@Math Revolution

Math Revolution

87 posts
4 GMATGuruNY

The Princeton Review Teacher

85 posts
5 Brent@GMATPrepNow

GMAT Prep Now Teacher

68 posts
See More Top Beat The GMAT Experts