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LM
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There are 99 workers in a mine. Each worker has a identity 25 Sep 2007, 18:27
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There are 99 workers in a mine. Each worker has a identity number from 1 to 99 and no two workers share the same identity number. During a disaster drill exercise all the workers leave the mine one-by-one in a completely random manner. What is the probability that the first four mine workers off the mine will leave in order of increasing identity numbers ( e.g., #2, then # 10, then #97, then #98, etc. ) ?

( A ) 1/64

( B) 1/48

( C ) 1/36

( D ) 1/24

( E) 1/16



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ywilfred
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There are 99 workers in a mine. Each worker has a identity 25 Sep 2007, 18:36
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Isn't this the same question as the one mgmat posted on their challenge?
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beckee529
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There are 99 workers in a mine. Each worker has a identity 25 Sep 2007, 21:47
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ywilfred
Isn't this the same question as the one mgmat posted on their challenge?
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yes! eeerie-ly similar if you ask me..

https://www.gmatclub.com/forum/t52818
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LM
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There are 99 workers in a mine. Each worker has a identity 26 Sep 2007, 00:34
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ywilfred
Isn't this the same question as the one mgmat posted on their challenge?

yes! eeerie-ly similar if you ask me..

https://www.gmatclub.com/forum/t52818
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Hi,

I just checked the link, and yes you are right, the questions is same. Now the point shouldn't be, it's the same or it isn't, the point for all of us being here in GClub is to be able to solve the questions. Could you guys please focus and help me reaching the solution instead of similarities between them?

Regards,
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KillerSquirrel
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There are 99 workers in a mine. Each worker has a identity 26 Sep 2007, 01:11
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The trick is to understand that the question really asks us for the odds that in a group of four workes (w1 - w4) ---> w1< w2 < w3 < w4.

Since we have four workers, the total possibable arrangements is 4! = 24 but in only one possibable arrangement can w1 < w2 < w3< w4 so the probability is 1/24.

Hence for any four workers chosen the probability is 1/24 , no matter how many workers we started with (just ignore the 99 number).

the answer is (D)

:)
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ywilfred
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There are 99 workers in a mine. Each worker has a identity 26 Sep 2007, 01:16
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LM
beckee529
ywilfred
Isn't this the same question as the one mgmat posted on their challenge?

yes! eeerie-ly similar if you ask me..

https://www.gmatclub.com/forum/t52818

Hi,

I just checked the link, and yes you are right, the questions is same. Now the point shouldn't be, it's the same or it isn't, the point for all of us being here in GClub is to be able to solve the questions. Could you guys please focus and help me reaching the solution instead of similarities between them?

Regards,
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okay, i thought there was a solution on that link... anyway, squirrel solved it .. :wink:
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ethan_casta
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There are 99 workers in a mine. Each worker has a identity 26 Sep 2007, 09:34
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this is a tough problem. i was trying all sorts of useless things and then i figured i'd just read the answer to save my time.

i'm glad i did.



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Hi there,
This topic has been closed and archived due to inactivity or violation of community quality standards. No more replies are possible here.
Where to now? Join ongoing discussions on thousands of quality questions in our Quantitative Questions Forum
Still interested in this question? Check out the "Best Topics" block above for a better discussion on this exact question, as well as several more related questions.
Thank you for understanding, and happy exploring!