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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 the probability of Sita getting selected to a school... tagged by: BTGmoderatorLU ##### This topic has 3 expert replies and 0 member replies ### Top Member ## If the probability of Sita getting selected to a school... If the probability of Sita getting selected to a school is 20% and she applied to 3 schools. What is the probability that she will get selected in at least one school? A. 24/125 B. 21/125 C. 61/125 D. 12/125 E. 18/125 The OA is C. I'm confused with this PS question. Experts, any suggestion about how to solve? I don't understand this question. Thanks in advance. ### GMAT/MBA Expert Elite Legendary Member Joined 23 Jun 2013 Posted: 10197 messages Followed by: 497 members Upvotes: 2867 GMAT Score: 800 Hi LUANDATO, We're told that the probability of Sita getting selected to any individual school is 20% and that she applied to 3 schools. We're asked for the probability that she will get selected to AT LEAST one school. With these types of probability questions, it's often easiest to calculate the probability of what you DON'T WANT - and then subtract that fraction from 1 to determine the probability of what you DO want. The question asks for the probability that she will get selected to AT LEAST one school, so we'll calculate the probability that she will get selected to 0 schools. A 20% chance of getting selected means an 80% chance of NOT getting selected. Since the answers are fractions, we should write 80% as 4/5: (Not selected)(Not selected)(Not selected) = (4/5)(4/5)(4/5) = 64/125 chance of getting selected by 0 schools Thus, he probability that she will get selected to AT LEAST one school is... 1 - 64/125 = 61/125 Final Answer: C GMAT assassins aren't born, they're made, Rich _________________ Contact Rich at Rich.C@empowergmat.com ### GMAT/MBA Expert GMAT Instructor Joined 04 Oct 2017 Posted: 551 messages Followed by: 11 members Upvotes: 180 Quote: If the probability of Sita getting selected to a school is 20% and she applied to 3 schools. What is the probability that she will get selected in at least one school? A. 24/125 B. 21/125 C. 61/125 D. 12/125 E. 18/125 The OA is C. I'm confused with this PS question. Experts, any suggestion about how to solve? I don't understand this question. Thanks in advance. Hi LUANDATO, Let's take a look at your question. The probability of Sita getting selected to a school = 20% = 20/100 = 1/5 This question can easily be solved by calculating the probability of opposite event. The probability of Sita not getting selected to a school = 1 - 1/5 = 4/5 Probability that Sita not getting selected at all three schools can be calculated as: $$=\left(\frac{4}{5}\right)^3=\frac{65}{125}$$ Now we can solve the probability of Sita getting selected in atleast one school as: $$=1-\frac{64}{125}=\frac{125-64}{125}=\frac{61}{125}$$ Therefore, Option C is correct. Hope it helps. I am available if you's like any follow up. _________________ GMAT Prep From The Economist We offer 70+ point score improvement money back guarantee. Our average student improves 98 points. Free 7-Day Test Prep with Economist GMAT Tutor - Receive free access to the top-rated GMAT prep course including a 1-on-1 strategy session, 2 full-length tests, and 5 ask-a-tutor messages. Get started now. ### GMAT/MBA Expert GMAT Instructor Joined 09 Apr 2015 Posted: 1465 messages Followed by: 19 members Upvotes: 39 LUANDATO wrote: If the probability of Sita getting selected to a school is 20% and she applied to 3 schools. What is the probability that she will get selected in at least one school? A. 24/125 B. 21/125 C. 61/125 D. 12/125 E. 18/125 We can use the equation: P(selected into at least 1 school) = 1 - P(selected to no schools) P(selected to no schools) = 4/5 x 4/5 x 4/5 = 64/125 Thus, P(selected into at least 1 school) = 1 - 64/125 = 61/125 Answer: C _________________ Jeffrey Miller Head of GMAT Instruction jeff@targettestprep.com See why Target Test Prep is rated 5 out of 5 stars on BEAT the GMAT. Read our reviews • Magoosh Study with Magoosh GMAT prep 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 • 5 Day FREE Trial Study Smarter, Not Harder Available with Beat the GMAT members only code • 1 Hour Free BEAT THE GMAT EXCLUSIVE Available with Beat the GMAT members only code • Get 300+ Practice Questions 25 Video lessons and 6 Webinars for FREE 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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