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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 ## Cars J and K are making the trip from City A to City B. Car ##### This topic has 2 expert replies and 0 member replies ### Top Member ## Cars J and K are making the trip from City A to City B. Car ## Timer 00:00 ## Your Answer A B C D E ## Global Stats Difficult Cars J and K are making the trip from City A to City B. Car J departs from City A 15 minutes after Car K does, and both cars travel along the same route. If Car K travels at a constant speed that is 80% the constant speed of Car J, then how many minutes will elapse before Car J catches up to Car K? A) 20 B) 45 C) 60 D) 75 E) 1230 OA C Source: Princeton Review ### GMAT/MBA Expert GMAT Instructor Joined 25 Apr 2015 Posted: 2852 messages Followed by: 18 members Upvotes: 43 Top Reply BTGmoderatorDC wrote: Cars J and K are making the trip from City A to City B. Car J departs from City A 15 minutes after Car K does, and both cars travel along the same route. If Car K travels at a constant speed that is 80% the constant speed of Car J, then how many minutes will elapse before Car J catches up to Car K? A) 20 B) 45 C) 60 D) 75 E) 1230 OA C Source: Princeton Review We can let r = the rate of Car J, and so 0.8r = the rate of Car K. We also let t = the time of Car J, in minutes, and (t + 15) = the time of Car K, in minutes, when Car J catches up to Car K. We can create the equation: rt = 0.8r(t + 15) rt = 0.8rt + 12r t = 0.8t + 12 0.2t = 12 t = 60 Answer: C _________________ Scott Woodbury-Stewart Founder and CEO scott@targettestprep.com See why Target Test Prep is rated 5 out of 5 stars on BEAT the GMAT. Read our reviews ### GMAT/MBA Expert GMAT Instructor Joined 25 May 2010 Posted: 15362 messages Followed by: 1866 members Upvotes: 13060 GMAT Score: 790 Top Reply BTGmoderatorDC wrote: Cars J and K are making the trip from City A to City B. Car J departs from City A 15 minutes after Car K does, and both cars travel along the same route. If Car K travels at a constant speed that is 80% the constant speed of Car J, then how many minutes will elapse before Car J catches up to Car K? A) 20 B) 45 C) 60 D) 75 E) 1230 Since J catches up to K, J and K travel the same distance. Let t = J's time. Since K leaves 15 minutes earlier than J, K's time = t+15. Rate and time have a RECIPROCAL RELATIONSHIP. Since K's rate is 80% of J's rate, the ratio of K's rate to J's rate = 8/10 = 4/5. Thus, the ratio of K's time to J's time = 5/4: (t+15)/t = 5/4 4t + 60 = 5t 60 = t 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. • Magoosh Study with Magoosh GMAT prep 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 GMAT Exam Know how you'd score today for$0

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