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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 ## A jar contains exactly 100 marbles; each marble contains tagged by: swerve ##### This topic has 1 expert reply and 0 member replies ### Top Member ## A jar contains exactly 100 marbles; each marble contains ## Timer 00:00 ## Your Answer A B C D E ## Global Stats Difficult A jar contains exactly 100 marbles; each marble contains exactly 2 colors. Forty-three of the marbles are part-green and 21 of the marbles are part-red. If 3 marbles are to be selected at random, what is the probability that at least 2 of them contain no blue? 1) 61 of the marbles are part-orange. 2) 74 of the marbles are part-yellow. The OA is C Source: Princeton Review ### GMAT/MBA Expert GMAT Instructor Joined 02 Jun 2008 Posted: 2475 messages Followed by: 351 members Upvotes: 1090 GMAT Score: 780 If we have 100 marbles, and each marble is made up of 2 colours, we have 200 colours in total. Using either Statement alone, we haven't accounted for very many of the colours, so we could have quite a few half-blue marbles or we could have none, and our probability of picking half-blue marbles could be nonzero or zero. But using both Statements, we have accounted for 43+21+61+74 = 199 of the 200 colours. So we have either 0 half-blue marbles or 1 half-blue marble. In either case, if we pick two or more marbles, we'll never pick two half-blue marbles, and the probability the question is asking for must be zero. So the answer is C. _________________ If you are looking for online GMAT math tutoring, or if you are interested in buying my advanced Quant books and problem sets, please contact me at ianstewartgmat at gmail.com • Free Veritas GMAT Class Experience Lesson 1 Live Free Available with Beat the GMAT members only code • 5 Day FREE Trial Study Smarter, Not Harder 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 • Award-winning private GMAT tutoring Register now and save up to$200

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