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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 ## Robots X, Y, and Z each assembled components at their tagged by: AAPL ##### This topic has 1 expert reply and 0 member replies ### Top Member ## Robots X, Y, and Z each assembled components at their ## Timer 00:00 ## Your Answer A B C D E ## Global Stats Difficult GMAT Prep Robots X, Y, and Z each assemble components at their respective constant rates. If $$r(x)$$ is the ratio of robot X's constant rate to robot Z's constant rate and $$r(y)$$ is the ratio of robot Y's constant rate to robot Z's constant rate, is robot Z's constant rate the greatest of the three? 1) $$r_x < r_y$$ 2) $$r_y < 1$$ OA C ### GMAT/MBA Expert GMAT Instructor Joined 25 May 2010 Posted: 15344 messages Followed by: 1864 members Upvotes: 13060 GMAT Score: 790 AAPL wrote: GMAT Prep Robots X, Y, and Z each assemble components at their respective constant rates. If $$r(x)$$ is the ratio of robot X's constant rate to robot Z's constant rate and $$r(y)$$ is the ratio of robot Y's constant rate to robot Z's constant rate, is robot Z's constant rate the greatest of the three? 1) $$r_x < r_y$$ 2) $$r_y < 1$$ Let X = X's rate, Y = Y's rate, and Z = Z's rate. r(x) = the ratio of X's rate to Z's rate = X/Z. r(y) = the ratio of Y's rate to Z's rate = Y/Z. Note: X, Y and Z all represent rates and thus must be POSITIVE. Statement 1: r(x) < r(y) In other words: X/Z < Y/Z. Since Z>0, we can multiply each side by Z: (X/Z) * Z < (Y/Z) * Z X < Y. No way to determine whether Z is the greatest of the 3 rates. INSUFFICIENT. Statement 2: r(y) < 1 In other words: Y/Z < 1. Since Z>0, we can multiply each side by Z: (Y/Z) * Z < 1 * Z Y < Z. No way to determine whether Z is the greatest of the 3 rates. INSUFFICIENT. Statements combined: Since X < Y and Y < Z, we get: X < Y < Z Thus, Z is the greatest of the 3 rates. SUFFICIENT. The correct answer is C. _________________ Mitch Hunt Private Tutor for the GMAT and GRE GMATGuruNY@gmail.com If you find one of my posts helpful, please take a moment to click on the "UPVOTE" icon. Available for tutoring in NYC and long-distance. For more information, please email me at GMATGuruNY@gmail.com. Student Review #1 Student Review #2 Student Review #3 Free GMAT Practice Test How can you improve your test score if you don't know your baseline score? Take a free online practice exam. Get started on achieving your dream score today! Sign up now. • Get 300+ Practice Questions 25 Video lessons and 6 Webinars for FREE Available with Beat the GMAT members only code • 1 Hour Free 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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