Math questions from any Manhattan Prep GMAT Computer Adaptive Test.
shantascherla
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Absolute Question -CAT exam 3A

by shantascherla Fri Apr 15, 2011 1:59 pm

If a and b are integers, and |a| > |b|, is a · |b| < a - b?

(1) a < 0

(2) ab 0

OA e

The official explanation is pretty long - and if was wondering if there are any tricks that can help in resolving the question in 2-3 minutes
tim
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Re: Absolute Question -CAT exam 3A

by tim Fri Apr 15, 2011 9:12 pm

sure - try plugging in numbers..
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entebbe21
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Re: Absolute Question -CAT exam 3A

by entebbe21 Thu Apr 28, 2011 2:06 am

well, lets use numbers.

|a|>|b|
when a=-2, b = -1

a*|b|<a-b?

so,

-2*1<-2+1?
-2<-1 - YES.

when a=-2, b=1

-2*1<-2-1?
-2<-3?
NO.

so statement 1 is Ins.

st. 2:
a*b=0
so B is zero (A cannot be = 0 bc his distance from zero is bigger than b's distance |a|>|b|)

so:a*|b|<a-b?
0<a

we disregard stm.1 so a can be <>0
means - no answer here as well.


if we put both of them in:
i dont c why u cannot tell if

0<a when a<0. it will always be smaller than 0 what am i missing?
jnelson0612
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Re: Absolute Question -CAT exam 3A

by jnelson0612 Sat Apr 30, 2011 1:22 pm

The problem is that statement 2 is written incorrectly.

It should actually read:

2) a*b > 0,
NOT a*b=0.

Check out this thread which has a lot of information about this problem: if-a-and-b-are-integers-and-a-b-is-a-b-a-b-t9437.html
Jamie Nelson
ManhattanGMAT Instructor