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If r/s = 2/5 , what is the value of rs ?

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If r/s = 2/5 , what is the value of rs ? [#permalink] New post 30 May 2012, 16:27
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A
B
C
D
E

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100% (01:42) correct 0% (00:00) wrong based on 25 sessions
If r/s = 2/5 , what is the value of rs ?

(1) If 2s/5 is multiplied by 12, the result is 25.
(2) If 5r/2 is multiplied by 4, the result is 250.

Though it looks like standard D (two unknowns, two equations : one equation in question stem and one equation from each answer choices) I'm getting two different values of r and 2 from two statements.

So in such cases, the answer should be E. What do you guys think?
Or am I making another silly calculation mistake?

Source : Jeff Sachmann DS challenge
[Reveal] Spoiler: OA
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Re: If r/s = 2/5 , what is the value of rs ? [#permalink] New post 31 May 2012, 01:40
Expert's post
If r/s = 2/5 , what is the value of rs ?

(1) If 2s/5 is multiplied by 12, the result is 25. We have that 2s/5*12=25 and r/s=2/5 --> we can solve for r and s and thus get the value of rs. Sufficient. Notice that from this statement r=25/12 and s=125/24.

(2) If 5r/2 is multiplied by 4, the result is 250. We have that 5r/2*4=250 and r/s=2/5 --> we can solve for r and s and thus get the value of rs. Sufficient. Notice that from this statement r=25 and s=125/2.

Now, technically answer should be D, as EACH statement ALONE is sufficient to answer the question.

But even though formal answer to the question is D (EACH statement ALONE is sufficient), this is not a realistic GMAT question, as: on the GMAT, two data sufficiency statements always provide TRUE information and these statements never contradict each other.

So, the question is flawed. You won't see such a question on the GMAT.

Hope it's clear.
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Re: If r/s = 2/5 , what is the value of rs ? [#permalink] New post 31 May 2012, 05:25
Thanks Bunuel! Its perfectly clear now.
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Re: If r/s = 2/5 , what is the value of rs ? [#permalink] New post 31 May 2012, 09:52
interesting

Thanks Piya and Bunuel. This was informative and helpful
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Re: If r/s = 2/5 , what is the value of rs ? [#permalink] New post 05 Jun 2012, 03:56
Yes very good information. Thanks Bunuel
Re: If r/s = 2/5 , what is the value of rs ?   [#permalink] 05 Jun 2012, 03:56
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