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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 ## 10! + 9! can be rewritten as: tagged by: Brent@GMATPrepNow ##### This topic has 3 expert replies and 1 member reply ### Top Member ## 10! + 9! can be rewritten as: 10! + 9! can be rewritten as: A. 9!(10) B. 11!/10 C. (10!)^2*9 D. (9!)^2 + 10 E. 19! OA is B My approach 10! + 9! 10*9! + 9! Taking out 9! common 9!(10 + 1) 9!(11) Now from here i don't know how to proceed. So, i am bit stuck here. However, when i was reviewing, i played around with B 11!/10 (11 * 10 * 9!) / 10 (11)9! Same outcome as what i got when i solved earlier, but how to get B on my first approach. Thanks ### GMAT/MBA Expert GMAT Instructor Joined 08 Dec 2008 Posted: 12435 messages Followed by: 1244 members Upvotes: 5254 GMAT Score: 770 Top Reply vinni.k wrote: Brent@GMATPrepNow wrote: You're almost there! You have (11)9! Check the answer choice.....(11)9! isn't there! So, we'll need to check each answer choice. Thanks Brent, So, the right approach for this question is to check each of the answer choices. Once you've rewritten 10! + 9! as (11)9! and discovered that your answer is not among the answer choices, you can EITHER try to rewrite (11)9! so that it matches one of the answer choices, OR you can try to rewrite each answer choice so that it matches (11)9!. The second option is most likely the faster approach. Cheers, Brent _________________ Brent Hanneson â€“ Creator of GMATPrepNow.com Use our video course along with Sign up for our free Question of the Day emails And check out all of our 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 08 Dec 2008 Posted: 12435 messages Followed by: 1244 members Upvotes: 5254 GMAT Score: 770 Top Reply vinni.k wrote: 10! + 9! can be rewritten as: A. 9!(10) B. 11!/10 C. (10!)^2*9 D. (9!)^2 + 10 E. 19! OA is B My approach 10! + 9! 10*9! + 9! Taking out 9! common 9!(10 + 1) 9!(11) Now from here i don't know how to proceed. So, i am bit stuck here. However, when i was reviewing, i played around with B 11!/10 (11 * 10 * 9!) / 10 (11)9! Same outcome as what i got when i solved earlier, but how to get B on my first approach. Thanks You're almost there! You have (11)9! Check the answer choice.....(11)9! isn't there! So, we'll need to check each answer choice. A. 9!(10) We can clearly see that this is not equal to (11)9! ELIMINATE A B. 11!/10 11!/10 = (11)(10)(9)(8)(7)(6)(5)(4)(3)(2)(1)/(10) = (11)(9)(8)(7)(6)(5)(4)(3)(2)(1) = (11)(9!) = B Cheers, Brent _________________ Brent Hanneson â€“ Creator of GMATPrepNow.com Use our video course along with Sign up for our free Question of the Day emails And check out all of our 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! ### Top Member Master | Next Rank: 500 Posts Joined 17 Apr 2011 Posted: 420 messages Followed by: 2 members Upvotes: 6 Test Date: 2016 Target GMAT Score: 700+ GMAT Score: 620 Brent@GMATPrepNow wrote: You're almost there! You have (11)9! Check the answer choice.....(11)9! isn't there! So, we'll need to check each answer choice. Thanks Brent, So, the right approach for this question is to check each of the answer choices. ### GMAT/MBA Expert GMAT Instructor Joined 09 Apr 2015 Posted: 1461 messages Followed by: 17 members Upvotes: 39 vinni.k wrote: 10! + 9! can be rewritten as: A. 9!(10) B. 11!/10 C. (10!)^2*9 D. (9!)^2 + 10 E. 19! 10! + 9! = 10 x 9! + 9! = 9!(10 + 1) = 9!(11) = 11!/10 Answer: B _________________ Jeffrey Miller Head of GMAT Instruction • Award-winning private GMAT tutoring Register now and save up to$200

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