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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 ## Gmat prep problem - Expert's help preferred ##### This topic has 1 expert reply and 4 member replies ## Gmat prep problem - Expert's help preferred Hi I really need some better explanation for this, not answered well anywhere! ### GMAT/MBA Expert GMAT Instructor Joined 25 May 2010 Posted: 15383 messages Followed by: 1872 members Upvotes: 13060 GMAT Score: 790 Each time the ball descends a level, it has 2 options: to fall TO THE LEFT or TO THE RIGHT. Since the ball descends 3 levels, and there are 2 options for each level, the total number of routes = 2*2*2 = 8. There is only 1 way to land in slot 1 (straight down the left side of the triangle) and only 1 way to land in slot 4 (straight down the right side of the triangle). Each of the 6 remaining routes leads to the one of the two middle slots. Since the probability of landing in either of the two middle slots is the same, 3 of these 6 remaining routes lead to slot 2. Thus, P(slot 2) = 3/8. 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. Master | Next Rank: 500 Posts Joined 11 Jun 2011 Posted: 370 messages Followed by: 2 members Upvotes: 27 Test Date: Late November Target GMAT Score: 700+ Thanks Mitch. I should directly Pm you when I need exceptional solutions! Master | Next Rank: 500 Posts Joined 01 Aug 2008 Posted: 242 messages Upvotes: 6 Test Date: 15/02/2011 Target GMAT Score: 750 [quote="GMATGuruNY"]Each time the ball descends a level, it has 2 options: to fall TO THE LEFT or TO THE RIGHT. Since the ball descends 3 levels, and there are 2 options for each level, the total number of routes = 2*2*2 = 8. [color=red]There is only 1 way to land in slot 1 (straight down the left side of the triangle) and only 1 way to land in slot 4 (straight down the right side of the triangle). Each of the 6 remaining routes leads to the one of the two middle slots.[/color] Since the probability of landing in either of the two middle slots is the same, 3 of these 6 remaining routes lead to slot 2. Thus, P(slot 2) = 3/8. The correct answer is [spoiler]D[/spoiler].[/quote] Please explain the red coloured portion as I could not understand it. Senior | Next Rank: 100 Posts Joined 21 Dec 2009 Posted: 57 messages Upvotes: 17 Target GMAT Score: 730 Such a simple explanation could only be possible for Mitch.Thanks! Legendary Member Joined 26 Apr 2011 Posted: 1239 messages Followed by: 25 members Upvotes: 233 Test Date: 26/06/2012 Target GMAT Score: 720 GMAT Score: 680 Quote: There is only 1 way to land in slot 1 (straight down the left side of the triangle) and only 1 way to land in slot 4 (straight down the right side of the triangle). Each of the 6 remaining routes leads to the one of the two middle slots. Please explain the red coloured portion as I could not understand it. To hit cell numbered 1, the ball has to come all the way left, if it goes right anywhere in the middle it won't hit cell 1. So there is only 1 way. [see the picture if you don't understand it] Similar manner to hit 4 it has to go all the way right - one way. Total 8 ways, one for cell 1, one for cell 4 and remaining 6 for cell 2 and 3. _________________ Getting defeated is just a temporary notion, giving it up is what makes it permanent. https://gmatandbeyond.blogspot.in/ • Get 300+ Practice Questions 25 Video lessons and 6 Webinars for FREE Available with Beat the GMAT members only code • Free Trial & Practice Exam BEAT THE GMAT EXCLUSIVE 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 • Award-winning private GMAT tutoring Register now and save up to$200

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