Register    Login    Search    Rss Feeds

Forums Home » Ask An Instructor » GMAT Math » GMAT Prep Math


 Page 1 of 1 [ 5 posts ] 



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

Is |x| = y-z?

Author Message
Guest
 Post subject: Is |x| = y-z?
 Post Posted: Sat Apr 28, 2007 6:08 pm 
Is |x| = y-z?

1) x+y = z

2) x<0

Can you please explain how to approach this question? I answered it correctly but I don't think I fully understand how I came up with the answer.

Thank you!
Top 
ayang
 Post subject: GMAT Prep Absolute Value problem
 Post Posted: Sun Apr 29, 2007 2:49 am 
Offline
ManhattanGMAT Staff


Posts: 43
Is |x| = y-z?

1) x+y = z

2) x<0


Statement 2 alone: The first thing to do is take the easy statement, Statement 2, which is clearly not sufficient by itself. Eliminate B and D.

Statement 1 alone:

Statement 1 should be manipulated to find x:

x + y = z
x = z - y

If x = z - y, is |x| = y-z?

Note that y - z = - (z - y). So the question asks, is |x| = - x?

From statement 1 alone, you don't know if this is the case, so eliminate answer choice A.

Statements 1 and 2 together:

From statement 2, you know that x is negative. So - x will equal |x|.
From statement 1, you know that x = z - y

Therefore:
- x = y -z
|x| = y-z

Answer choice C.

Hope that this is helpful! - Andrew





Can you please explain how to approach this question? I answered it correctly but I don't think I fully understand how I came up with the answer.

Thank you!
Top 
Guest
 Post subject:
 Post Posted: Sun Apr 29, 2007 1:01 pm 
Thank you, Andrew! This is very helpful!

Jenna
Top 
abdul_tt
 Post subject: Re: Is |x| = y-z?
 Post Posted: Thu Sep 15, 2011 11:25 am 
Offline
Students


Posts: 2
Ron,
Could you please tell me how you'd approach this question. I'm satisfied with the above answer, but wondering if there is another approach to this question.
Top 
RonPurewal
 Post subject: Re: Is |x| = y-z?
 Post Posted: Tue Sep 20, 2011 7:28 am 
Offline
ManhattanGMAT Staff


Posts: 7146
abdul_tt wrote:
Ron,
Could you please tell me how you'd approach this question. I'm satisfied with the above answer, but wondering if there is another approach to this question.


here's another thread:
is-x-y-z-t8626.html

you can also plug in numbers.

statement (2): obviously insufficient, as there is no information at all about y or z

statement (1):
x, y, z = 1, 2, 3 --> gives "no" the question
x, y, z = 0, 0, 0 --> gives "yes" to the question
so, insufficient

together:
go ahead and plug in as many sets of x, y, z as you want (as long as they satisfy both conditions); you will notice that you get "yes" every time. just keep plugging until you are convinced.

so, (c)
Top 
Display posts from previous:  Sort by  
 
 Page 1 of 1 [ 5 posts ] 





Who is online

Users browsing this forum: No registered users and 1 guest

 
 

 
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: