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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 ## Engine A can work 5 hours on 10 liters of fuel ##### This topic has 3 expert replies and 0 member replies ## Engine A can work 5 hours on 10 liters of fuel Engine A can work 5 hours on 10 liters of fuel while engine B can work 3 hours on 15 liters of fuel. If engine efficiency is defined as a reciprocal to the hourly fuel consumption rate, what is the ratio of the efficiency of engine B to that of engine A? A)2/5 B)1/2 C)2 D)5/2 E)3 OA: A What is hourly fuel consumption rate ? ### GMAT/MBA Expert Legendary Member Joined 14 Jan 2015 Posted: 2667 messages Followed by: 122 members Upvotes: 1153 GMAT Score: 770 NandishSS wrote: Engine A can work 5 hours on 10 liters of fuel while engine B can work 3 hours on 15 liters of fuel. If engine efficiency is defined as a reciprocal to the hourly fuel consumption rate, what is the ratio of the efficiency of engine B to that of engine A? A)2/5 B)1/2 C)2 D)5/2 E)3 OA: A What is hourly fuel consumption rate ? You can think of any rate as "task/time period." So here the fuel consumption rate for A is 10 liters/5 hours = 2 liters/hour and the consumption rate for B is 15 liters/3hours = 5 liters per hours. If the engine efficiency is the reciprocal of this figure, then the engine efficiency for A is 1/2 and for B it's 1/5. We want the ratio of the efficiency of B to the efficiency of A, or (1/5)/(1/2) = 1/5 * 2/1 = 2/5. The answer is A _________________ Veritas Prep | GMAT Instructor Veritas Prep Reviews Save$100 off any live Veritas Prep GMAT Course

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Note, also, that it's often the case that a question will have both the correct answer and a trap answer among the answer choices. In this case, because we're dealing with reciprocals, it stands to reason that there's a good chance 2/5 and 5/2 represent a correct answer and a trap. (Of course, there are exceptions.) If you're able to see that B's engine efficiency is less than that of A's, you can jump right to the answer almost immediately.

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Save $100 off any live Veritas Prep GMAT Course Enroll in a Veritas Prep GMAT class completely for FREE. Wondering if a GMAT course is right for you? Attend the first class session of an actual GMAT course, either in-person or live online, and see for yourself why so many students choose to work with Veritas Prep. Find a class now! ### GMAT/MBA Expert GMAT Instructor Joined 22 Aug 2016 Posted: 1975 messages Followed by: 30 members Upvotes: 470 NandishSS wrote: Engine A can work 5 hours on 10 liters of fuel while engine B can work 3 hours on 15 liters of fuel. If engine efficiency is defined as a reciprocal to the hourly fuel consumption rate, what is the ratio of the efficiency of engine B to that of engine A? A)2/5 B)1/2 C)2 D)5/2 E)3 OA: A What is hourly fuel consumption rate ? "Hourly fuel consumption rate" means the amount of fuel consumed in an hour measured in Liter per hour Thus, efficiency = Reciprocal of (Liter per hour) = Hour per liter Hope this helps! Download free ebook: Manhattan Review GMAT Quantitative Question Bank Guide -Jay _________________ Manhattan Review GMAT Prep Locations: New York | Jakarta | Nanjing | Berlin | and many more... Schedule your free consultation with an experienced GMAT Prep Advisor! Click here. • Magoosh Study with Magoosh GMAT prep 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 to$200

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