Register    Login    Search    Rss Feeds

Forums Home » Ask An Instructor » GMAT Math » Manhattan GMAT CAT Math


 Page 1 of 1 [ 2 posts ] 



  Print view Print view Previous topic Previous topic | Next topic Next topic
 

If ab ≠ 0, does a = b? (1) xa = xb (2) x = x2

Author Message
rajivranprasad
 Post subject: If ab ≠ 0, does a = b? (1) xa = xb (2) x = x2
 Post Posted: Fri Feb 03, 2012 6:56 am 
Offline
Forum Guests


Posts: 1
can u explain ds question
i am unable to get the explaination given.
Top 
jnelson0612
 Post subject: Re: If ab ≠ 0, does a = b? (1) xa = xb (2) x = x2
 Post Posted: Sun Feb 05, 2012 5:41 pm 
Offline
ManhattanGMAT Staff


Posts: 1857
GMATHKD wrote:
can u explain ds question
i am unable to get the explaination given.


If ab ≠ 0, does a = b? (1) xa = xb (2) x = x^2

I assume that the answer is E. Let's take this apart piece by piece.

First, ab does not equal zero means that neither a nor b is zero. Our question is does a=b?

Let's start with statement 2, since it is far easier:

2) x=x^2
That tell us nothing about a or b. Cross off BD.

1) xa=xb
Let's plug in numbers. If x=1, then a=b.
However, is x=0, then a could be any number and b could be any number. When they are multiplied by zero by will become zero, and thus they do not have to be the same. Thus, 1 is insufficient. Cross off 1.

1+2) Let's go back to statement 2. If x=x^2, then x could be 0 or 1. As we saw when we looked at statement 1, because of this a could be equal to b or a might not be equal to b. Insufficient. The answer must be E.

_________________
Jamie Nelson
ManhattanGMAT Instructor
Top 
Display posts from previous:  Sort by  
 
 Page 1 of 1 [ 2 posts ] 





Who is online

Users browsing this forum: No registered users and 0 guests

 
 

 
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to: