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What is the median number of employees assigned per project [#permalink]
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17 Apr 2010, 08:00
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What is the median number of employees assigned per project for the projects at Company Z? (1) 25 percent of the projects at Company Z have 4 or more employees assigned to each project. (2) 35 percent of the projects at Company Z have 2 or fewer employees assigned to each project. OPEN DISCUSSION OF THIS QUESTION IS HERE: http://gmatclub.com/forum/whatisthem ... 31892.html
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Re: What is the median number of employees assigned per project [#permalink]
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17 Apr 2010, 09:05
S1. Insuff: we have no idea how the rest of the employees are assigned S2. Insuff: we have no idea how the rest of the employees are assigned Together, we know the middle 40% of employees are assigned to projects with 3 people. The median value will fall within this middle 40%, so the value must be 3, and the statements together are sufficient. Answer is C
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Re: What is the median number of employees assigned per project [#permalink]
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24 Apr 2010, 09:29
TheGmatTutor wrote: S1. Insuff: we have no idea how the rest of the employees are assigned S2. Insuff: we have no idea how the rest of the employees are assigned
Together, we know the middle 40% of employees are assigned to projects with 3 people. The median value will fall within this middle 40%, so the value must be 3, and the statements together are sufficient.
Answer is C Didn't really understand the explanation ... IMO , the answer should be E. Can somebody please clarify ?



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Re: What is the median number of employees assigned per project [#permalink]
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24 Apr 2010, 15:40
not enough information for either A or B. If we combined Together i am guessing 55% of the projects have atleast 2 people in each project so the median falls in this range...so the answer may be C ?



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Re: What is the median number of employees assigned per project [#permalink]
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24 Apr 2010, 15:41
nilesh376 what is the answer?. Can someone explain this clearly?.



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Re: What is the median number of employees assigned per project [#permalink]
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24 Apr 2010, 23:42
Bunuel or somebody else can you please suggest your thoughts ?



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Re: What is the median number of employees assigned per project [#permalink]
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25 Apr 2010, 04:18
What is the median number of employees assigned per project for the projects at Company Z? (1) 25 percent of the projects at Company Z have 4 or more employees assigned to each project. (2) 35 percent of the projects at Company Z have 2 or fewer employees assigned to each project. (1)+(2) 40% of the projects have exactly 3 employees assigned to each of them, as no other option is left for 100%(25%+35%)=40% of the projects. Consider there are 100 projects: \(\{p_1, p_2, ... ,p_{100}\}\). The values of \(p_1\) to \(p_{35}\) will be 0, 1, or 2; the values of \(p_{36}\) to \(p_{75}\) will be exactly 3; the values of \(p_{76}\) to \(p_{100}\) will be 4 or more. \(Median=\frac{p_{50}+p_{51}}{2}=\frac{3+3}{2}=3\). For example list can be: \(\{2, 2, 2, ...,(p_{35}=2), (p_{36}=3), 3, ...,(p_{75}=3), (p_{76}=4), 4, ...,(p_{100}=4)\}\); OR: \(\{0, 0, 1,1,1,2, 2, ...,(p_{35}=2), (p_{36}=3), 3, ...,(p_{75}=3), (p_{76}=4), 5,7, 27, ...,(p_{100}=10000)\}\) (of course there are a lot of other breakdowns). In any case median=3. Answer: C. Hope it's clear.
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Re: What is the median number of employees assigned per project [#permalink]
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25 Apr 2010, 06:09
Bunuel wrote: What is the median number of employees assigned per project for the projects at Company Z?
(1) 25 percent of the projects at Company Z have 4 or more employees assigned to each project. (2) 35 percent of the projects at Company Z have 2 or fewer employees assigned to each project.
(1)+(2) 40% of the projects have exactly 3 employees assigned to each of them, as no other option is left for 100%(25%+35%)=40% of the projects.
Consider there are 100 projects: \(\{p_1, p_2, ... ,p_{100}\}\). The values of \(p_1\) to \(p_{35}\) will be 0, 1, or 2; the values of \(p_{36}\) to \(p_{75}\) will be exactly 3; the values of \(p_{76}\) to \(p_{100}\) will be 4 or more. \(Median=\frac{p_{50}+p_{51}}{2}=\frac{3+3}{2}=3\).
For example list can be: \(\{2, 2, 2, ...,(p_{35}=2), (p_{36}=3), 3, ...,(p_{75}=3), (p_{76}=4), 4, ...,(p_{100}=4)\}\); OR: \(\{0, 0, 1,1,1,2, 2, ...,(p_{35}=2), (p_{36}=3), 3, ...,(p_{75}=3), (p_{76}=4), 5,7, 27, ...,(p_{100}=10000)\}\) (of course there are a lot of other breakdowns).
In any case median=3.
Answer: C.
Hope it's clear. Got it . Thanks Bunuel ... as always..



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Re: What is the median number of employees assigned per project [#permalink]
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26 Jul 2010, 13:15
Pls explain in breif the following question, thanx in advance
What is the median number of employees assigned per project for the projects at Company Z?
A. 25 percent of the projects at Company Z have 4 or more employees assigned to each project B. 35 percent of the projects at Company Z have 2 or fewer employees assigned to each projects



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Re: What is the median number of employees assigned per project [#permalink]
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27 Jul 2010, 01:31
I myself find Bunuel's answer is clear, but not fully satisfactory. The question asks for median value, so the total number of project should be significant. It is quite obvious to figure out that 40% of the projects is conducted by 3 employees. Let's call total number of projects N, since 0.25*N, 0.40*N, and 0.35*N are intergers (since they are number of projects), N must be a positive multiple of 20. Therefore N is greater or equal than 20 projects. Let's take N=20 for instance:  7 projects with strictly less than 3 employees  8 projects with exactly 3 employees  5 projects with strictly more than 3 employees Therefore, the median value is equal to 3.
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Re: What is the median number of employees assigned per project [#permalink]
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31 Jul 2010, 02:23
What is the meadian number of employees assigned per project for the projects at company Z? 1 25 percent of the projects at company Z have 4 or more employees assigned to each project.
2 35 percent of the projects at Company Z have 2 or fewer employees assigned to each project.
thanks



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Re: What is the median number of employees assigned per project [#permalink]
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17 Aug 2010, 06:39
I think C. 1) does not tell you about median nor does 2). However together they account for 50%. The remaining 50% of projects must have employees 3, and hence median 3
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Re: What is the median number of employees assigned per project [#permalink]
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17 Aug 2010, 07:39
1) 25% of projects have 4+ members  25% 4+ members  75% less than 4 members Alone its not sufficient
2) 35% of projects have 2 or less  35% of projects have 2 or less members  65% of projects have more than 2 members Alone not sufficient
Both: 25% have 4 or more 35% have 2 or less 40% have 3 exactly meaning that more projects have 3 members than any other number. You have your median but need both statements to complete.
C



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