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Five people, Ada, Ben, Cathy, Dan, and Eliza, are lining up for a [#permalink]
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Updated on: 11 Jan 2017, 10:24
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Five people, Ada, Ben, Cathy, Dan, and Eliza, are lining up for a photo. What is the probability that none of the three girls will stand next to one another? (A) 0.1 (B) 0.2 (C) 0.3 (D) 0.4 (E) 0.5
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Originally posted by DrAB on 07 Sep 2016, 09:32.
Last edited by Bunuel on 11 Jan 2017, 10:24, edited 1 time in total.
Edited the options.



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Re: Five people, Ada, Ben, Cathy, Dan, and Eliza, are lining up for a [#permalink]
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07 Sep 2016, 10:26
DrAB wrote: Five people, Ada, Ben, Cathy, Dan, and Eliza, are lining up for a photo. What is the probability that none of the three girls will stand next to one another?
(A) 0,1 (B) 0,2 (C) 0,3 (D) 0,4 (E) 0,5 Out of 5 , then the only position the three girls can take are 1, 3 and 5th so they are have 3! ways of standing in those position and remaining 2 boys can have 2! ways. So Probability = \(\frac{3! * 2!}{5!} =\frac{1}{10}\) Answer is A



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Re: Five people, Ada, Ben, Cathy, Dan, and Eliza, are lining up for a [#permalink]
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07 Sep 2016, 18:39
Senthil1981 wrote: DrAB wrote: Five people, Ada, Ben, Cathy, Dan, and Eliza, are lining up for a photo. What is the probability that none of the three girls will stand next to one another?
(A) 0,1 (B) 0,2 (C) 0,3 (D) 0,4 (E) 0,5 Out of 5 , then the only position the three girls can take are 1, 3 and 5th so they are have 3! ways of standing in those position and remaining 2 boys can have 2! ways. So Probability = \(\frac{3! * 2!}{5!} =\frac{1}{10}\) Answer is A This is a poorquality question. How can one tell there are 3 girls?



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Re: Five people, Ada, Ben, Cathy, Dan, and Eliza, are lining up for a [#permalink]
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07 Sep 2016, 20:19
I did it this way...
BTW we can tell the number of girls (although I though this should be more clear) because, based on the answer choices, we know there is at least ONE way they can stand all separate. So there are 3 girls and 2 boys.
Total number of options they could stay 5!=120
The number of ways for the girls to be separate
3*2*2*1*1=12 12/120=1/10



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Re: Five people, Ada, Ben, Cathy, Dan, and Eliza, are lining up for a [#permalink]
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07 Sep 2016, 20:42
Donnie84 wrote: Senthil1981 wrote: DrAB wrote: Five people, Ada, Ben, Cathy, Dan, and Eliza, are lining up for a photo. What is the probability that none of the three girls will stand next to one another?
(A) 0,1 (B) 0,2 (C) 0,3 (D) 0,4 (E) 0,5 Out of 5 , then the only position the three girls can take are 1, 3 and 5th so they are have 3! ways of standing in those position and remaining 2 boys can have 2! ways. So Probability = \(\frac{3! * 2!}{5!} =\frac{1}{10}\) Answer is A This is a poorquality question. How can one tell there are 3 girls? The question says "none of the three girls". Could this mean differently ?



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Re: Five people, Ada, Ben, Cathy, Dan, and Eliza, are lining up for a [#permalink]
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07 Sep 2016, 20:49
The question says "none of the three girls". Could this mean differently ?[/quote]
Ah, I missed that. +1 to you.
Still, I think an official question will have a clearer language than this one.



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Re: Five people, Ada, Ben, Cathy, Dan, and Eliza, are lining up for a [#permalink]
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07 Sep 2016, 21:01
Donnie84 wrote: The question says "none of the three girls". Could this mean differently ? Ah, I missed that. +1 to you. Still, I think an official question will have a clearer language than this one.[/quote] It's true that this not in GMAT format since they have used "," instead of ".". Looks like European notation.



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Re: Five people, Ada, Ben, Cathy, Dan, and Eliza, are lining up for a [#permalink]
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04 Jan 2018, 15:58
Hi All, We're given 3 girls and 2 boys and told to put them in a line. We're asked for the probability that none of the three girls will stand next to one another. This question can be approached in a number of different ways. Here's how you can use permutations and probability to get to the correct answer: With 5 people, there are 5! = 120 possible arrangements. Lining up the 5 people, there's just one option for the 3 girls to NOT stand next to one another: GBGBG = (3)(2)(2)(1)(1) = 12 options Thus, the probability of the 3 girls NOT standing next to one another is 12/120 = 1/10 = 10% = .1 Final Answer: GMAT assassins aren't born, they're made, Rich
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Re: Five people, Ada, Ben, Cathy, Dan, and Eliza, are lining up for a
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