Question #122: OG12: on Page 283, explanation on page 330

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Am I missing something? b'cos I find this one ambiguous.

What is the volume of the rectangular solid?
1: Two adjacent faces of the solid have areas 15 and 24, respectively
2: Each of the two opposite faces of the solid has area 40.

statement 1 is NOT SUFFICIENT.

but there are 2 ways to interpret statement 2:

one:-
Each of the two opposite faces ==read as== each pair of opposite faces
In that case it is a cube with side 2root10
So, B is SUFFICIENT and so answer is B

two:-
Each of the two opposite faces ==read as== one pair of opposite faces
In that case their explanation works and so answer is C which is OG's answer

My question is what is the English meaning of "Each of the two opposite faces"? Is it "Each of, two opposite sides" or is it" Each of two, opposite sides"
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by electrico » Thu Apr 29, 2010 12:38 am
I guess Each of the two opposite faces means one pair of opposite faces .

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by Stuart@KaplanGMAT » Thu Apr 29, 2010 11:04 am
iamseer wrote:Am I missing something? b'cos I find this one ambiguous.

What is the volume of the rectangular solid?
1: Two adjacent faces of the solid have areas 15 and 24, respectively
2: Each of the two opposite faces of the solid has area 40.
Hi,

as you've noted, precise language is very important on the GMAT; so, it's vital to reproduce the wording verbatim when discussing ambiguity.

Q: What is the volume of a certain rectangular solid?

(1) Two adjacent faces of the solid have areas 15 and 24, respectively.

(2) Each of two opposite faces of the solid has area 40.

Adding definite articles to a statement completely changes the meaning; you'll not the bolded part of the actual question and that statement (2) doesn't actually include "the".

On the GMAT, "the" refers to something specific; you'll never see it used in the abstract as you posted in the question stem. You might see:

"What is the volume of the rectangular solid in the diagram above?"

or

"If a rectangular solid is inscribed in a cylindar with height 8 and radius 2pi, what is the volume of the rectangular solid?"

but never just:

"What is the volume of the rectangular solid?".

Your interpretation of the statement (2) that you posted is correct, but that's not the actual wording of the question. By using the phrase "Each of two opposite faces", the statement is clearly referring to just 1 pair of faces.

Here's another guideline, if you're ever unsure:

the two statements in DS will never contradict each other.

Under your interpretation of statement (2), it contradicts statement (1); recognizing that fact is enough to know that your interpretation is incorrect.
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by iamseer » Thu Apr 29, 2010 11:25 am
Thanks for the detailed explanation Stuart. That is indeed helpful.

My apologies for the error. But am glad I made that error. In a way got to learn more from you :)
Here's another guideline, if you're ever unsure:

the two statements in DS will never contradict each other.
Thanks again for this additional piece of information.
"Choose to chance the rapids and dance the tides"