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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 ## If r and s are positive integers... ##### This topic has 2 expert replies and 0 member replies ## If r and s are positive integers... ## Timer 00:00 ## Your Answer A B C D E ## Global Stats Difficult If r and s are positive integers, is r + s even? 1) r is even. 2) s is even. C Source: Official Guide 2020 ### GMAT/MBA Expert GMAT Instructor Joined 08 Dec 2008 Posted: 12989 messages Followed by: 1249 members Upvotes: 5254 GMAT Score: 770 AbeNeedsAnswers wrote: If r and s are positive integers, is r + s even? 1) r is even. 2) s is even. Given: r and s are positive integers Target question: Is r + s even? Statement 1: r is even. Since we have no information about s, we cannot determine whether r + s is even Since we cannot answer the target question with certainty, statement 1 is NOT SUFFICIENT Statement 2: s is even Since we have no information about r, we cannot determine whether r + s is even Since we cannot answer the target question with certainty, statement 2 is NOT SUFFICIENT Statements 1 and 2 combined Statement 1 tells us that r is EVEN Statement 2 tells us that s is EVEN Since EVEN + EVEN = EVEN, we know that r + s is EVEN Since we can answer the target question with certainty, the combined statements are SUFFICIENT Answer: C 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 Elite Legendary Member Joined 23 Jun 2013 Posted: 10197 messages Followed by: 496 members Upvotes: 2867 GMAT Score: 800 Hi All, We're told that R and S are POSITIVE INTEGERS. We're asked if R+S is EVEN. This is a YES/NO question and can be solved with Number Properties and/or by TESTing VALUES. To start, you might find it helpful to write down a few Number Property rules: (Even) + (Even) = Even (Even) + (Odd) = Odd (Odd) + (Odd) = Even Since R and S are both INTEGERS, to end up with a sum that is EVEN, then BOTH numbers must either be EVEN or ODD. Otherwise, the sum will be ODD. 1) R is EVEN. IF... S = EVEN, then R+S will be EVEN. S = ODD, then R+S will be ODD. Fact 1 is INSUFFICIENT 2) S is EVEN. IF... R = EVEN, then R+S will be EVEN. R = ODD, then R+S will be ODD. Fact 2 is INSUFFICIENT Combined, we know... R is EVEN. S is EVEN. Thus, R+S must be EVEN and the answer to the question is ALWAYS YES. Combined, SUFFICIENT Final Answer: C GMAT assassins aren't born, they're made, Rich _________________ Contact Rich at Rich.C@empowergmat.com • Award-winning private GMAT tutoring Register now and save up to$200

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