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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 ## In a certain pet shop, 1/3 of the pets are dogs and 1/5 of tagged by: AAPL ##### This topic has 2 expert replies and 0 member replies ### Top Member ## In a certain pet shop, 1/3 of the pets are dogs and 1/5 of ## Timer 00:00 ## Your Answer A B C D E ## Global Stats Difficult GMAT Prep In a certain pet shop, 1/3 of the pets are dogs and 1/5 of the pets are birds. How many of the pets are dogs? 1) There are 30 birds at the pet shop. 2) There are 20 more dogs than birds at the pet shop. OA D ### GMAT/MBA Expert GMAT Instructor Joined 08 Dec 2008 Posted: 12982 messages Followed by: 1249 members Upvotes: 5254 GMAT Score: 770 AAPL wrote: GMAT Prep In a certain pet shop, 1/3 of the pets are dogs and 1/5 of the pets are birds. How many of the pets are dogs? 1) There are 30 birds at the pet shop. 2) There are 20 more dogs than birds at the pet shop. OA D Target question: How many of the pets are dogs? Given: 1/3 of pets are dogs & 1/5 of pets are birds Let T = TOTAL number of pets. So, T/3 = number of dogs And T/5 = number of birds Statement 1: There are 30 birds at the pet shop So, T/5 = 30 This means that T = 150, which means T/3 = 50 (i.e., there are 50 dogs) Since we can answer the target question with certainty, statement 1 is SUFFICIENT Statement 2: There are 20 more dogs than birds at the pet shop. In other words, (# of birds) + 20 = # of dogs We can now write: T/5 + 20 = T/3 IMPORTANT: We could solve this equation for T, but we're not going to waste time doing so. We need only recognize that we could solve the equation for T, which means we can definitely find the value of T/3 (the number of dogs) Since we can answer the target question with certainty, statement 2 is SUFFICIENT Answer: D Cheers, Brent _________________ Brent Hanneson â€“ Creator of GMATPrepNow.com Use my video course along with Sign up for free Question of the Day emails And check out all of these free resources GMAT Prep Now's comprehensive video course can be used in conjunction with Beat The GMATâ€™s FREE 60-Day Study Guide and reach your target score in 2 months! ### GMAT/MBA Expert GMAT Instructor Joined 25 May 2010 Posted: 15348 messages Followed by: 1864 members Upvotes: 13060 GMAT Score: 790 AAPL wrote: GMAT Prep In a certain pet shop, 1/3 of the pets are dogs and 1/5 of the pets are birds. How many of the pets are dogs? 1) There are 30 birds at the pet shop. 2) There are 20 more dogs than birds at the pet shop. Alternate approach: To determine the ratio of birds to dogs, plug in a TEST VALUE for the total number of pets. Let b = the number of birds and d = the number of dogs. Let the test value for the total number of pets = the LCM of 3 and 5 = 15. Since 1/5 are birds, b = 1/5 * 15 = 3. Since 1/3 are dogs, d = 1/3 * 15 = 5. Thus: b/d = 3/5. Statement 1: There are 30 birds at the pet shop Since b/d = 3/5 = 30/50, b=30 and d=50. SUFFICIENT. Statement 2: There are 20 more dogs than birds at the pet shop The values yielded by statement 1 -- b=30 and d=50 -- are the only values for b and d such that b/d = 3/5 and d=b+20. 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. • Award-winning private GMAT tutoring Register now and save up to$200

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