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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 ## OG QR question 83 ##### This topic has 2 member replies ## OG QR question 83 If k and n are integers, is n divisible by 7? 1) n - 3 = 2k 2) 2k - 4 is divisible by 7. In the explanation when adding both statements together, I don't see the equation can be expressed as: n = 2k -4 + 7 Senior | Next Rank: 100 Posts Joined 11 Jul 2008 Posted: 58 messages Upvotes: 4 Test Date: 8/16/2008 Target GMAT Score: 730+ The book does a terrible job explaining the solution. Basically you need to remember that if two numbers are each multiples of the same number, the sum will also be a multiple of that number. 1) n=2k+3, tells us what n is but doesn't tell us if it is evenly divisible by 7 - INSUF 2) tells us nothing about n - INSUF 1+2) 2k-4 is a multiple of 7 according to #2, and 7 by definition is a multiple of 7, so add the two to rearrange the equation and you get 2k-4+7=2k+3. 2k+3 must now be a multiple of 7 since it is a sum of two numbers that are a multiple of 7. Combine that with statment 1 and we now know that n is a multipe of 7. FYI you could keep adding any multiples of 7 to 2k-4 and the sum would be a multiple of 7, but since statement 1 makes it only necessary to add 7. Hope that helps. Junior | Next Rank: 30 Posts Joined 30 Apr 2008 Posted: 22 messages Upvotes: 5 thanks. that makes perfect sense now. • 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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