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is this powerprep math question correct? i think it's wrong.

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This is a question from the powerprep testing software the GMAT used to offer.

Currently there are 50 picture books on a shelf in the children's section of a library. IF these books were to be placed on smaller shelves with 30 picture books on each shelf how many of the smaller shelves would be needed to hold all of these books?

(1) The number of smaller shelves needed is 6 more than the current number of shelves.

(2) Currently there are 9 shelves in the children's section.


I say that the answer is B, 2 only.

The explanation from the powerprep states that:

1 yields the equation --> 30(s+6) = 50s therefore s = 9 end of story.
Obivously 2 works. SO they say each alone is fine.

WHen i worked the problem i agree 9 works, but so does 8. If you have 8 rows of books originally you have 50(8)= 400 books. For 400 books to be distributed on shelves of 30 books each you would need 400/30 = 13.333333 shelves, which mean you'd need 14 shelves (you can't have 1/3 of a shelf). 14 = 8+6. Statement 1 is valid for both 9 and 8, therefore you can't solely use it.

how am i wrong here?

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by gabriel » Wed Dec 05, 2007 10:40 am
Post the question verbatim, can comment on it only after I read it, but the logic you have used seems right.

Regards

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by thunderdogg » Wed Dec 05, 2007 10:59 am
gabriel wrote:Post the question verbatim, can comment on it only after I read it, but the logic you have used seems right.

Regards
that is verbatim. i can post it again:
--------------------------

Currently there are 50 picture books on a shelf in the children's section of a library. IF these books were to be placed on smaller shelves with 30 picture books on each shelf how many of the smaller shelves would be needed to hold all of these books?

(1) The number of smaller shelves needed is 6 more than the current number of shelves.

(2) Currently there are 9 shelves in the children's section.

--------------------

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by thunderdogg » Wed Dec 05, 2007 11:04 am
here is a screen shot.
Attachments
mathquestion.jpg
mathquestion.jpg (58.36 KiB) Viewed 108 times

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by thunderdogg » Wed Dec 05, 2007 11:06 am
i guess the with 30 picture books on each shelf statement is supposed to indicate that you MUST HAVE 30 on each shelf, which would make it so 1 is fine stand alone. I guess in the end it just seems like a poorly worded question.

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by gabriel » Thu Dec 06, 2007 1:18 pm
I agree with Mike, you had typed the question wrong, just goes to show how much difference a single word can make

btw this question should be in the DS question ... moved to the DS section.