Math questions from any Manhattan Prep GMAT Computer Adaptive Test.
alexander.gundry
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If ABCD is a trapezoid, where AB is parallel to CD...

by alexander.gundry Tue Aug 09, 2011 8:50 am

Hi. I am having trouble with the problem below. I do not understand why you can't divide both sides by 2 to get the height of AB and CD (the two bases). I thought that the answer to this DS question was C because statement 1 gives you the bases of the trapezoid (Ab + CD = 6) and statement 2 gives you the height of the trapezoid. But, because you can't divide by 2 in statement 1, it only provides you with Ab = CD - AB. (I can't post the picture but it is just a standard trapezoid. The question is called "Trap-ez") Thanks!

If ABCD is a trapezoid, where AB is parallel to CD, what is the area of ABCD?

(1) 2(AB) + CD = 12

(2) The height of the trapezoid is 5 inches
mithunsam
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Re: If ABCD is a trapezoid, where AB is parallel to CD...

by mithunsam Tue Aug 09, 2011 8:58 am

Is statement 1 2(AB) + CD = 12 or 2(AB + CD) = 12?

If it is 2(AB) + CD = 12 (as stated in your question), you cannot divide. Division gives you AB + CD/2 = 6 (not AB + CD = 6).
kjsullivan1382
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Re: If ABCD is a trapezoid, where AB is parallel to CD...

by kjsullivan1382 Tue Aug 09, 2011 11:35 pm

So, what's the answer to question? I concluded that both Statements 1 & 2 are necessary to answer the question.
mithunsam
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Re: If ABCD is a trapezoid, where AB is parallel to CD...

by mithunsam Wed Aug 10, 2011 4:48 pm

Answer should be E.

As I stated above, you cannot get the sum of bases from 2(AB) + CD = 12
jnelson0612
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Re: If ABCD is a trapezoid, where AB is parallel to CD...

by jnelson0612 Sun Sep 11, 2011 11:58 pm

If the question is stated correctly, I agree that the answer would be E.
Jamie Nelson
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