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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 ## The Lewiston Road Race is how many kilometers long? ##### This topic has 2 expert replies and 1 member reply ### Top Member ## The Lewiston Road Race is how many kilometers long? ## Timer 00:00 ## Your Answer A B C D E ## Global Stats Difficult The Lewiston Road Race is how many kilometers long? (1) It takes 2 more hours to complete the race at an average speed of 40 kilometers per hour than at an average speed of 50 kilometers per hour. (2) At an average speed of 20 kilometers per hour, it took Brett 10 hours to complete half the race. OA D Source: Princeton Review ### Top Member Legendary Member Joined 29 Oct 2017 Posted: 962 messages Followed by: 4 members Top Reply From 1: for average speed of 50 kilometers per hour time =t for average speed of 40 kilometers per hour time =t+2 50*t=40*(t+2). From here we will get t and multiply with 50 to get distance. No need to solve till last. Sufficient From 2: 10*20=d/2 hence sufficient. So option D. ### GMAT/MBA Expert GMAT Instructor Joined 09 Oct 2010 Posted: 1449 messages Followed by: 32 members Upvotes: 59 Top Reply BTGmoderatorDC wrote: The Lewiston Road Race is how many kilometers long? (1) It takes 2 more hours to complete the race at an average speed of 40 kilometers per hour than at an average speed of 50 kilometers per hour. (2) At an average speed of 20 kilometers per hour, it took Brett 10 hours to complete half the race. Source: Princeton Review $$? = D\,\,\,\,\,\left[ {{\rm{km}}} \right]$$ LetÂ´s use UNITS CONTROL, one of the most powerful tools of our method! $$\left( 1 \right)\,\,\,\left( {\,\,\left[ {{\rm{km}}} \right] \cdot {{\left[ {\rm{h}} \right]} \over {\left[ {{\rm{km}}} \right]}}\,\, = \,\,\left[ {\rm{h}} \right]\,} \right)\,\,\,\,\,\, \Rightarrow \,\,\,\,\,\,D \cdot {1 \over {40}} - D \cdot {1 \over {50}} = 2\,\,\,\,\left[ {\rm{h}} \right]\,\,\,\,\,\,\,\, \Rightarrow \,\,\,\,\,\,\,{\rm{SUFF}}.\,\,\,\,\,\,\,\,\,\left( {{1^{{\rm{st}}}}\,\,{\rm{degree}}\,\,{\rm{equation}}\,\,{\rm{in}}\,\,D} \right)$$ $$\left( 2 \right)\,\,\,?\,\, = \,\,2 \cdot 10\,{\rm{h}}\,\, \cdot \,\,{{20\,\,{\rm{km}}} \over {1\,\,{\rm{h}}}}\,\, = 400\,\,\,\,\left[ {\,{\rm{km}}\,} \right]\,\,\,\,\,\,\, \Rightarrow \,\,\,\,\,\,\,{\rm{SUFF}}.\,$$ 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 May 2010 Posted: 15348 messages Followed by: 1864 members Upvotes: 13060 GMAT Score: 790 BTGmoderatorDC wrote: The Lewiston Road Race is how many kilometers long? (1) It takes 2 more hours to complete the race at an average speed of 40 kilometers per hour than at an average speed of 50 kilometers per hour. (2) At an average speed of 20 kilometers per hour, it took Brett 10 hours to complete half the race. Statement 1: Rate and time have a RECIPROCAL relationship. A rate ratio of (40kph) : (50kph) = 4:5 implies a time ratio of 5:4 = 10:8. The time ratio in blue implies that -- for the time at 40kph to be 2 hours more than the time at 50kph -- the time at 40kph must be 10 hours, while the time at 50kph must be 8 hours. Since it takes 10 hours to complete the race at a speed of 40kph, the race = rt = 40*10 = 400 kilometers. SUFFICIENT. Statement 2: When Brett travels at a speed of 20kph for 10 hours, the distance = rt = 20*10 = 200 kilometers. Since these 200 kilometers constitute half the race, the entire race = 400 kilometers. SUFFICIENT. 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. • Get 300+ Practice Questions 25 Video lessons and 6 Webinars for FREE Available with Beat the GMAT members only code • Magoosh Study with Magoosh GMAT prep Available with Beat the GMAT members only code • Award-winning private GMAT tutoring Register now and save up to$200

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