Andy, George, and Sally are a team of consultants working on : GMAT Data Sufficiency (DS)
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# Andy, George, and Sally are a team of consultants working on

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Andy, George, and Sally are a team of consultants working on [#permalink]

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17 May 2010, 16:17
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Andy, George, and Sally are a team of consultants working on Project Alpha. They have an 8 hour deadline to complete the project. The team members work at constant rates throughout the 8 hour period. If the team of three has to begin work now and no one else can work on this project, will Project Alpha be completed by the deadline?

(1) Sally can finish the project alone in 4k+7 hours, where k is a positive integer with a minimum value of 1 and a maximum value of 5.

(2) Working alone, Georgia will take 2k+1 hours, and Andy will take 3+2k hours, where k is a positive integer with a minimum value of 1 and a maximum value of 5.
[Reveal] Spoiler: OA

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Re: m02 #7 (DS) -- Project Alpha [#permalink]

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17 May 2010, 19:02
Without looking at the reveal. I have to say that I think it is not possible for them to complete the project in 8 hours. Thus we can answer the question and the answer is C both statements are needed in combination to complete the answer. The limits of Sally's ability are between 11 and 27 hours solo. Georgia from 3 to 11 hours solo. Lastly Andy 5-13 hours solo. Additively they will not be able to finish the project in the alloted time.

I will check out the reveal and see if I was right.
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Re: m02 #7 (DS) -- Project Alpha [#permalink]

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17 May 2010, 19:08
Okay I checked out the reveal and I had it totally upside down. I added up the slowest limit of their work. This seems like a good idea but understanding that Georgia and Andy could do it themselves, (making statement #2 sufficient) was not a possibility that i had explored. Gotta stick to your system. First is #1 sufficient?, then # 2? then the combination? I just assumed that it had to be the combination since Sally was not addressed in #1. Good question.
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Re: m02 #7 (DS) -- Project Alpha [#permalink]

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18 May 2010, 02:46
Please explain..If statement 2 is sufficient why not statement 1?
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Re: m02 #7 (DS) -- Project Alpha [#permalink]

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18 May 2010, 05:10
pardeepattri wrote:
Please explain..If statement 2 is sufficient why not statement 1?

(1) Sally can finish the project alone in 4k+7 hours, where k is a positive integer with a minimum value of 1 and a maximum value of 5.

Insufficient- Because it just mentions that sally can complete the work in between 11( when K=1) hours and 27 ( when k =5) hours but we dont have any info about the rest of the people.

(2) Working alone, Georgia will take 2k+1 hours, and Andy will take 3+2k hours, where k is a positive integer with a minimum value of 1 and a maximum value of 5.

Sufficient -
Georgia can complete the work in between 3 hours and 11 hours ,

Similarly Sally can complete the work in 5 hours and 13 hours

Now lets calculate the worst case scenario for these 2 together ( i.e when K =5 and they take the maximum time to complete the work)

$$\frac{1}{5} + \frac{1}{13} = \frac{1}{x}$$

$$x = \frac{5*13}{5+13} = \frac{65}{18} = 3.6$$ ( approx)

So basically Georgia and Sally can complete the work in 3.6 hours even without Andy and hence they all can definitely complete the work within 8 hours.
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Re: m02 #7 (DS) -- Project Alpha [#permalink]

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18 May 2010, 07:54
nitishmahajan wrote:
pardeepattri wrote:
Please explain..If statement 2 is sufficient why not statement 1?

(1) Sally can finish the project alone in 4k+7 hours, where k is a positive integer with a minimum value of 1 and a maximum value of 5.

Insufficient- Because it just mentions that sally can complete the work in between 11( when K=1) hours and 27 ( when k =5) hours but we dont have any info about the rest of the people.

(2) Working alone, Georgia will take 2k+1 hours, and Andy will take 3+2k hours, where k is a positive integer with a minimum value of 1 and a maximum value of 5.

Sufficient -
Georgia can complete the work in between 3 hours and 11 hours ,

Similarly Sally can complete the work in 5 hours and 13 hours

Now lets calculate the worst case scenario for these 2 together ( i.e when K =5 and they take the maximum time to complete the work)

$$\frac{1}{5} + \frac{1}{13} = \frac{1}{x}$$

$$x = \frac{5*13}{5+13} = \frac{65}{18} = 3.6$$ ( approx)

So basically Georgia and Sally can complete the work in 3.6 hours even without Andy and hence they all can definitely complete the work within 8 hours.

Looks like a mistake.

it should be

$$\frac{1}{11} + \frac{1}{13} = \frac{1}{x}$$

$$x = \frac{11*13}{11+13} = 5$$ ( approx)

Still the answer will be B
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Re: m02 #7 (DS) -- Project Alpha [#permalink]

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18 May 2010, 07:58
onedayill wrote:
nitishmahajan wrote:
pardeepattri wrote:
Please explain..If statement 2 is sufficient why not statement 1?

(1) Sally can finish the project alone in 4k+7 hours, where k is a positive integer with a minimum value of 1 and a maximum value of 5.

Insufficient- Because it just mentions that sally can complete the work in between 11( when K=1) hours and 27 ( when k =5) hours but we dont have any info about the rest of the people.

(2) Working alone, Georgia will take 2k+1 hours, and Andy will take 3+2k hours, where k is a positive integer with a minimum value of 1 and a maximum value of 5.

Sufficient -
Georgia can complete the work in between 3 hours and 11 hours ,

Similarly Sally can complete the work in 5 hours and 13 hours

Now lets calculate the worst case scenario for these 2 together ( i.e when K =5 and they take the maximum time to complete the work)

$$\frac{1}{5} + \frac{1}{13} = \frac{1}{x}$$

$$x = \frac{5*13}{5+13} = \frac{65}{18} = 3.6$$ ( approx)

So basically Georgia and Sally can complete the work in 3.6 hours even without Andy and hence they all can definitely complete the work within 8 hours.

Looks like a mistake.

it should be

$$\frac{1}{11} + \frac{1}{13} = \frac{1}{x}$$

$$x = \frac{11*13}{11+13} = 5$$ ( approx)

Still the answer will be B

Oh yeah, thats true, my mistake, it should have been 11 and 13, but anyway answer B will still hold.

Thanks mate
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Re: m02 #7 (DS) -- Project Alpha [#permalink]

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20 Nov 2010, 02:43
Guys, I am not a native speaker, yet for me 'will' in below sentence:
"If the team of three has to begin work now and no one else can work on this project, will Project Alpha be completed by the deadline?"
means there shall be a 100% guarantee the project will be completed.

However, both gents MAY NEED more than 8 hours to finish the projects, because their number of hours is flexible.

Therefore, for me this question appears as not worded correctly and the answer shall be E.

Alternatively, if we change the question to
"If the team of three has to begin work now and no one else can work on this project, IS THERE A POSSIBILITY for Project Alpha to be completed by the deadline?"
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Re: m02 #7 (DS) -- Project Alpha [#permalink]

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20 Nov 2010, 05:38
Ans has to be B,
The slowest rate at which Georgia and Andy can work in 1 hr. is 8/15
In 8 hours, then can do almost 5 times the work
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Re: Andy, George, and Sally are a team of consultants working on [#permalink]

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23 Sep 2012, 05:52
I couldn't get previous explanations and I found below with an example

Andy, George and Sally are a team of consultants working on Project Alpha. They have an eight hour deadline to complete the project. The team members work at constant rates throughout the eight hour period. If the team of three has to begin work now and no one else can work on this project, will Project Alpha be completed by the deadline?

1.Sally can finish the project alone in 4k + 7 hours, where k is a positive integer with a minimum value of 1 and a maximum value of 5.
2.Working alone, George will take 2k + 1 hours and Andy will take 3 + 2k hours, where k is a positive integer with a minimum value of 1 and a maximum value of 5

Statement 1 as you said is insufficient as we don't have any info about the rates of the other ppl.

From Statement two, Lets assume that a total of 143 pages need to be typed in 8 hrs. For andy and george, Lets assume that k=5 so Andy finishes 143 pages by himself in 13 hrs and George finishes 143 pages by himself in 11 hours.

Andy's Rate=143/13=11 pages/hr So in 8 hrs he will finish 88 pages
George's Rate=143/11=13 pages/hr so in 8 hrs he will finish 104 pages. So in 8 hrs if Andy and George alone can finish 192 pages, with Sally's help they'd we able to finish even more in 8 hrs over exceeding the target of 143 pages. Hence SUFFICIENT.
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Re: Andy, George, and Sally are a team of consultants working on [#permalink]

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24 Sep 2012, 23:33
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R2I4D wrote:
Andy, George, and Sally are a team of consultants working on Project Alpha. They have an 8 hour deadline to complete the project. The team members work at constant rates throughout the 8 hour period. If the team of three has to begin work now and no one else can work on this project, will Project Alpha be completed by the deadline?

(1) Sally can finish the project alone in 4k+7 hours, where k is a positive integer with a minimum value of 1 and a maximum value of 5.

(2) Working alone, Georgia will take 2k+1 hours, and Andy will take 3+2k hours, where k is a positive integer with a minimum value of 1 and a maximum value of 5.

The wording in this question is really bad, and not at all GMAT-like. For one thing, there is no need to make k a variable in each statement (a real GMAT question would never do that; instead k would have a single fixed value within the range given - they'd say "where 1 < k < 5"). Then if you choose to combine the statements, because the letters have been turned into variables, it isn't at all clear if the k referred to in Statement 1 must have the same value as the k referred to in Statement 2.

Regardless, one can see why Statement 2 is sufficient fairly quickly. Even in the worst case, Georgia would take 11 hours alone, and Andy 13 hours. Two workers exactly like Andy would take 13/2 = 6.5 hours to do the job. Well, Georgia is faster than Andy, so one worker like Georgia and one worker like Andy must take less time than two workers like Andy, so Andy and Georgia together must take less than 6.5 hours. So even in the worst case, the job is certainly finished in less than 6.5 hours, and the answer is B.
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Re: Andy, George, and Sally are a team of consultants working on   [#permalink] 24 Sep 2012, 23:33
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