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A contest will consist of n questions, each of which is to
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18 Nov 2006, 08:48
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A contest will consist of n questions, each of which is to be answered wither "True" or "False". Anyone who answers all n questions correctly will be a winner. What is the least value of n for which the probability is less than 1/1000 that a person who randomly guesses the answer to each question will be a winner? A. 5 B. 10 C. 50 D. 100 E. 1000
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Re: A contest will consist of n questions, each of which is to
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21 Feb 2012, 10:25




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Re: A contest will consist of n questions, each of which is to
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21 Feb 2012, 10:54
+1 B The probability of answering right randomly is 1/2. So, the probability of winning the contest is \(\frac{1}{2} * \frac{1}{2} *....\frac{1}{2} = \frac{1}{2^n}\) \(2^9 = 512\) 2^(10) \(= 1024\) So, n must be at least 10. ANSWER B
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Re: A contest will consist of n questions, each of which is to
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10 Jan 2014, 09:54
SimaQ wrote: A contest will consist of n questions, each of which is to be answered wither "True" or "False". Anyone who answers all n questions correctly will be a winner. What is the least value of n for which the probability is less than 1/1000 that a person who randomly guesses the answer to each question will be a winner?
A. 5 B. 10 C. 50 D. 100 E. 1000 Min 'n' for 2^n >=1000 2^9 = 512 Then 2^10 >=1000 actually 1024 So B



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Re: A contest will consist of n questions, each of which is to
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30 Oct 2014, 21:40
(1/2)^n < 1/1000 (1/2)^n < (1/2)^3*(1/5)^3 Because 1/5 ~ (1/2)^2 n > 3 + 3*2 = 9
B



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Re: A contest will consist of n questions, each of which is to
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20 Jul 2017, 15:47
SimaQ wrote: A contest will consist of n questions, each of which is to be answered wither "True" or "False". Anyone who answers all n questions correctly will be a winner. What is the least value of n for which the probability is less than 1/1000 that a person who randomly guesses the answer to each question will be a winner?
A. 5 B. 10 C. 50 D. 100 E. 1000 Since the probability of correctly answering a question is ½, we need to determine the least value of n such that (1/2)^n < 1/1000. Since (1/2)^10 = 1/1024, the least value of n is 10. Answer: B
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Re: A contest will consist of n questions, each of which is to
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05 Jan 2019, 06:42
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