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# Six machines each working at the same

Author Message
VP
Joined: 18 May 2008
Posts: 1203
Six machines each working at the same [#permalink]

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13 Nov 2008, 03:46
Help

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Manager
Joined: 08 Aug 2008
Posts: 228

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13 Nov 2008, 07:29
more workers, lesser days....(inverse ratio since rates are same..)
6/x=8/12==> x=9

so 9-6 =3 additional workers reqd.
Manager
Joined: 23 Jul 2008
Posts: 189

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13 Nov 2008, 12:19
using unitary method
six m/cs------12 days
one m/cs------72 days
nine m/cs------8 days
Director
Joined: 14 Aug 2007
Posts: 704

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13 Nov 2008, 20:07
6 machines * Rate of individual machine (R) * 12 days = 1 work

Therefore R = 1/72

Let X be the total number of machines reqd to complete work in 8 days

we have,

X * 1/72 * 8 = 1

X =9

we need to know how many "additional" machines are reqd = 9 -6 = 3
VP
Joined: 18 May 2008
Posts: 1203

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13 Nov 2008, 21:30
Ohhhhhhhhhhhh. I didnt notice the word "additional" in the question and got 6 as the final answer.
This shows we shld read wht exactly is required in the question
Director
Joined: 14 Aug 2007
Posts: 704

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13 Nov 2008, 21:47
ritula wrote:
Ohhhhhhhhhhhh. I didnt notice the word "additional" in the question and got 6 as the final answer.
This shows we shld read wht exactly is required in the question

But then you should get 9 as answer right
or was it an upside down problem (9 6) :wink:

--== Message from GMAT Club Team ==--

This is not a quality discussion. It has been retired.

If you would like to discuss this question please re-post it in the respective forum. Thank you!

To review the GMAT Club's Forums Posting Guidelines, please follow these links: Quantitative | Verbal Please note - we may remove posts that do not follow our posting guidelines. Thank you.
Re: GMATCLUB- machines   [#permalink] 13 Nov 2008, 21:47
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# Six machines each working at the same

Moderator: chetan2u

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