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In nine independent trials, what is the probability that Outcome A
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18 Feb 2015, 04:51
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In nine independent trials, what is the probability that Outcome A
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18 Feb 2015, 07:27
Probability (Outcome A happens at least once)+probability(Outcome A does not happen even once)=1. Statement 1= Sufficient. statement 2= We know probability of A=1/3, p(A')=2/3 with these we can find out all the cases when A occurs at least once.sufficient.
ans=> D



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Re: In nine independent trials, what is the probability that Outcome A
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18 Feb 2015, 07:53
Bunuel wrote: In nine independent trials, what is the probability that Outcome A happens at least once?
(1) The probability that Outcome A does not happen even once in any of the nine trials is 0.026 (2) the probability of Outcome A resulting in a single trial is 1/3.
Kudos for a correct solution. Probability of Favorable Outcome + Probability of Unfavorable Outcome = 1
i.e. Probability of Favorable Outcome = 1  Probability of Unfavorable Outcomei.e. probability that Outcome A happens at least once = 1  Probability that Outcome A never happensStatement 1: P (A never happens) = 0.026i.e. P (A happens atleast once) = 1 0.026 = 0.974 SUFFICIENT Statement 2: probability of Outcome A resulting in a single trial is 1/3i.e. probability of Outcome A Not happen in a single trial is 1(1/3) = 2/3 i.e. Outcome A never happens in all 9 trials = (2/3)^9 = 0.026 i.e. P (A happens atleast once) = 1 0.026 = 0.974 SUFFICIENT Answer: Option
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Re: In nine independent trials, what is the probability that Outcome A
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18 Feb 2015, 08:43
Here we go:
St1: The probability that Outcome A does not happen even once in any of the nine trials is 0.026
We have been asked the probability that Outcome A happens at least once.
This can be calculate > (1  0.026)
Hence St1 is sufficient
St2 : the probability of Outcome A resulting in a single trial is 1/3. We can also calculate the probability of Outcome A not resulting in a single trial : (1  1/3) = 2/3
So we can find easily calculate the probability that Outcome A happens at least once by using above information.
Hence St2 is also sufficient
Option D is correct.



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Re: In nine independent trials, what is the probability that Outcome A
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22 Feb 2015, 12:08
Bunuel wrote: In nine independent trials, what is the probability that Outcome A happens at least once?
(1) The probability that Outcome A does not happen even once in any of the nine trials is 0.026 (2) the probability of Outcome A resulting in a single trial is 1/3.
Kudos for a correct solution. MAGOOSH OFFICIAL SOLUTIONWe know there are nine trials. To figure out the probability that Outcome A happens at least once, we would need a way to figure out the probability of A, P(A). Statement #1: this statement gives us the complement. The complement of (Outcome A happens at least once) is (Outcome A does not happen at all). Complementary probabilities have a sum of 1 — P(not K) = 1 – P(K). Therefore, using the complement rule, we could figure out that P(A happens at least once) = 1 – P(A doesn’t happen at all) = 1 – 0.026 = 0.974 This information allows us to answer the prompt question. This statement, alone and by itself, is sufficient. Statement #2: this statement gives us P(A), which would allow us to calculate the probability that A happens at least once in nine trials. This statement, alone and by itself, is sufficient. Both statement sufficient. Answer = D  See more at: http://magoosh.com/gmat/2013/gmatdata ... JzRXH.dpuf
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Re: In nine independent trials, what is the probability that Outcome A
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24 Feb 2015, 09:02
Ans Is D coz of the following Statement 1 is sufficient as this is giving us the case of when an event is not happening ...question asked is when the event happens atleast once i.e 1(when the event does not happens). Statement 2 is sufficient cause as we know the probability of event happening so we can find when atleast once.



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Re: In nine independent trials, what is the probability that Outcome A
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10 Dec 2017, 04:53
Bunuel niks18 VeritasPrepKarishmaQuote: In nine independent trials, what is the probability that Outcome A happens at least once?
(1) The probability that Outcome A does not happen even once in any of the nine trials is 0.026 (2) the probability of Outcome A resulting in a single trial is 1/3. For Statement 2: How can we link outcome of event A with independent events in question stem?
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Re: In nine independent trials, what is the probability that Outcome A
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30 May 2018, 23:05
adkikani wrote: Bunuel niks18 VeritasPrepKarishmaQuote: In nine independent trials, what is the probability that Outcome A happens at least once?
(1) The probability that Outcome A does not happen even once in any of the nine trials is 0.026 (2) the probability of Outcome A resulting in a single trial is 1/3. For Statement 2: How can we link outcome of event A with independent events in question stem? Though it is long time, let me try to explain how 2nd one is giving ans. 1st one is obvious. let say there are 3 balls in a pot A, B and C. and you need to select one(A) randomly. when it is asked at least one, that means you can be successful 9 times to any 1 time. but don't fail all 9 times. means One attempted 9 times and all those 9 times one selected B or C. So if we find the probability to fail every time. We can find the probability of at least one time. probability to fail one time is 2/3. so for failing 9 times will be \((2/3)^9\). pass at least one time will be 1  \((2/3)^9\). Hope That helps.
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Re: In nine independent trials, what is the probability that Outcome A &nbs
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