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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 ## Carlos runs a lap around the track in x seconds. His second tagged by: BTGmoderatorLU ##### This topic has 4 expert replies and 0 member replies ### Top Member ## Carlos runs a lap around the track in x seconds. His second ## Timer 00:00 ## Your Answer A B C D E ## Global Stats Difficult Source: Manhattan Prep Carlos runs a lap around the track in x seconds. His second lap is five seconds slower than the first lap, but the third lap is two seconds faster than the first lap. What is Carlosâ€™s average (arithmetic mean) number of minutes per lap, in terms of x? $$A.\ x-1$$ $$B.\ x+1$$ $$C.\ \frac{x-1}{60}$$ $$D.\ \frac{x+1}{60}$$ $$E.\ \frac{x+3}{60}$$ The OA is D ### GMAT/MBA Expert GMAT Instructor Joined 25 May 2010 Posted: 15025 messages Followed by: 1859 members Upvotes: 13060 GMAT Score: 790 BTGmoderatorLU wrote: Source: Manhattan Prep Carlos runs a lap around the track in x seconds. His second lap is five seconds slower than the first lap, but the third lap is two seconds faster than the first lap. What is Carlosâ€™s average (arithmetic mean) number of minutes per lap, in terms of x? $$A.\ x-1$$ $$B.\ x+1$$ $$C.\ \frac{x-1}{60}$$ $$D.\ \frac{x+1}{60}$$ $$E.\ \frac{x+3}{60}$$ Let x = 5 seconds for the first lap, implying 10 seconds for the second lap, 3 seconds for the third lap, and a total of 18 seconds for all 3 laps. (18 seconds)/(3 laps) = (6 seconds)/(1 lap) = 1/10 minute per lap. The correct answer must yield a value of 1/10 when x=5. Only D works: (x+1)/60 = (5+1)/60 = 6/60 = 1/10. The correct answer is D. _________________ 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. ### GMAT/MBA Expert Elite Legendary Member Joined 23 Jun 2013 Posted: 10020 messages Followed by: 494 members Upvotes: 2867 GMAT Score: 800 Hi All, We're told that Carlos runs a lap around the track in X SECONDS. His second lap is five SECONDS SLOWER than the first lap, but the third lap is two SECONDS FASTER than the first lap. We're asked for Carlosâ€™s average (arithmetic mean) number of MINUTES per LAP, in terms of X. This question can be solved rather easily by TESTing VALUES (as Mitch has shown). It can also be solved Algebraically, although you have to make sure to do the extra 'step' of converting seconds to minutes. To start, we know that the 3 times/lap are : X seconds, (X + 5) seconds and (X - 2) seconds, so the AVERAGE time per lap (in seconds) is: (X + X + 5 + X - 2)/3 = (3X + 3)/3 = (X + 1) seconds Since 1 minute = 60 seconds, to convert an answer "in seconds" to an answer "in minutes", we need to divide by 60... (X + 1)/60 Final Answer: D GMAT assassins aren't born, they're made, Rich _________________ Contact Rich at Rich.C@empowergmat.com ### GMAT/MBA Expert GMAT Instructor Joined 09 Oct 2010 Posted: 1125 messages Followed by: 29 members Upvotes: 59 BTGmoderatorLU wrote: Source: Manhattan Prep Carlos runs a lap around the track in x seconds. His second lap is five seconds slower than the first lap, but the third lap is two seconds faster than the first lap. What is Carlosâ€™s average (arithmetic mean) number of minutes per lap, in terms of x? $$A.\ x-1\,\,\,\,\,\,\,B.\ x+1\,\,\,\,\,\,\,C.\ \frac{x-1}{60}\,\,\,\,\,\,\,D.\ \frac{x+1}{60}\,\,\,\,\,\,\,E.\ \frac{x+3}{60}$$ $$?\,\,\,:\,\,\,\,\,\,f\left( x \right)\,\,\,{{\min } \over {{\rm{lap}}}}$$ \eqalign{ & {1^{{\rm{st}}}}\,{\rm{lap}}\,\,\,\, \to \,\,\,\,\,\,\,x\,\,\sec \cr & {2^{{\rm{nd}}}}\,{\rm{lap}}\,\,\,\, \to \,\,\,\,\,\left( {x + 5} \right)\,\,\sec \,\,\,\,\, \cr & {3^{{\rm{rd}}}}\,{\rm{lap}}\,\,\,\, \to \,\,\,\,\,\left( {x - 2} \right)\,\,\sec \,\, \cr} LetÂ´s use UNITS CONTROL, one of the most powerful tools of our method! $?\,\,\, = \,\,\,\,\frac{{\left( {3x + 3} \right)\,\,\sec }}{{3\,\,{\text{laps}}\,}}\,\,\,\left( {\frac{{1\,\,\min }}{{60\,\,\sec }}} \right)\,\,\,\, = \,\,\,\,\frac{{x + 1}}{{60}}\,\,\,\,\frac{{\min }}{{{\text{lap}}}}$ 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: 1808 messages Followed by: 14 members Upvotes: 43 BTGmoderatorLU wrote: Source: Manhattan Prep Carlos runs a lap around the track in x seconds. His second lap is five seconds slower than the first lap, but the third lap is two seconds faster than the first lap. What is Carlosâ€™s average (arithmetic mean) number of minutes per lap, in terms of x? $$A.\ x-1$$ $$B.\ x+1$$ $$C.\ \frac{x-1}{60}$$ $$D.\ \frac{x+1}{60}$$ $$E.\ \frac{x+3}{60}$$ The total number of seconds it takes Carlos to run the 3 laps is x + (x + 5) + (x - 2) = 3x + 3. So the number of seconds per lap is (3x + 3)/3 = x + 1, and hence, the number of minutes per lap is (x + 1)/60. Answer: D _________________ Scott Woodbury-Stewart Founder and CEO • Free Veritas GMAT Class Experience Lesson 1 Live Free 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 • Free Practice Test & Review How would you score if you took the GMAT Available with Beat the GMAT members only code • 5 Day FREE Trial Study Smarter, Not Harder 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 • Award-winning private GMAT tutoring Register now and save up to200

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