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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 particular state, 70 percent of the counties received.. tagged by: BTGmoderatorLU ##### This topic has 3 expert replies and 0 member replies ### Top Member ## In a particular state, 70 percent of the counties received.. In a particular state, 70 percent of the counties received some rain on Monday, and 65 percent of the counties received some rain on Tuesday. No rain fell either day in 25 percent of the counties in the state. What percent of the counties received some rain on Monday and Tuesday? A. 12.5% B. 40% C. 50% D. 60% E. 67.5% The OA is D. I'm confused by this PS question. Experts, any suggestion? Thanks in advance. ### GMAT/MBA Expert Legendary Member Joined 20 Jul 2017 Posted: 503 messages Followed by: 10 members Upvotes: 86 GMAT Score: 770 We can solve this problem by filling in the information we know using a double matrix. [img]https://cl.ly/3q3U1q2s3R1E[/img] Filling in only the information in the question gives us: [img]https://cl.ly/162J2X0m1u2c[/img] We want to know the number of counties that received some rain on both Monday and Tuesday. In other words, we want to find the value in the top left cell (Monday rain + Tuesday rain). Next, in any row that has two filled-in cells, we can use that information to fill in the third cell in the row: [img]https://cl.ly/2j420X0a023K[/img] Then again: [img]https://cl.ly/1x272X0e2e2L[/img] Then again: [img]https://cl.ly/3K1U1k3T3T3V[/img] So 60% of the counties received some rain on both Monday and Tuesday. _________________ Erika John - Content Manager/Lead Instructor https://gmat.prepscholar.com/gmat/s/ Get tutoring from me or another PrepScholar GMAT expert: https://gmat.prepscholar.com/gmat/s/tutoring/ Learn about our exclusive savings for BTG members (up to 25% off) and our 5 day free trial Check out our PrepScholar GMAT YouTube channel, and read our expert guides on the PrepScholar GMAT blog ### GMAT/MBA Expert Elite Legendary Member Joined 23 Jun 2013 Posted: 9939 messages Followed by: 492 members Upvotes: 2867 GMAT Score: 800 Hi LUANDATO, We're told that in a particular state, 70 percent of the counties received some rain on Monday, 65 percent of the counties received some rain on Tuesday and no rain fell either day in 25 percent of the counties in the state. We're asked for the percent of the counties that received some rain on Monday AND Tuesday. This prompt is an example of a standard 'Overlapping Sets' question and we can use the Overlapping Sets Formula to answer it. The Overlapping Sets Formula is... Total = (Group 1) + (Group 2) - (Both) + (Neither) In this prompt, Group 1 is the "Monday rain" group and Group 2 is the "Tuesday rain" group: Total = (Group 1) + (Group 2) - (Both) + (Neither) 100% = (70%) + (65%) - (Both) + (25%) 100% = 160% - (Both) Both = 60% Thus, 60% of the counties received rain on BOTH days. 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 Apr 2015 Posted: 1461 messages Followed by: 17 members Upvotes: 39 LUANDATO wrote: In a particular state, 70 percent of the counties received some rain on Monday, and 65 percent of the counties received some rain on Tuesday. No rain fell either day in 25 percent of the counties in the state. What percent of the counties received some rain on Monday and Tuesday? A. 12.5% B. 40% C. 50% D. 60% E. 67.5% We can use the following formula: 100 = rain on Monday + rain on Tuesday - rain on both + rain on neither 100 = 70 + 65 - both + 25 Both = 60 Answer:D _________________ Jeffrey Miller Head of GMAT Instruction • Get 300+ Practice Questions 25 Video lessons and 6 Webinars for FREE 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 • Free Veritas GMAT Class Experience Lesson 1 Live Free 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 GMAT Exam Know how you'd score today for$0

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