Register    Login    Search    Rss Feeds

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


 Page 1 of 1 [ 4 posts ] 



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

If -2x > 3y, is x negative?

Author Message
mdh3000
 Post subject: If -2x > 3y, is x negative?
 Post Posted: Tue Jun 03, 2008 7:54 pm 
If -2x > 3y, is x negative?

1) y > 0
2) 2x+5y-20=0

The correct answer is D (both sufficient).

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

Statement 1 is easy, x would have to be negative in order for -2x to be a positive number greater than 3y (since y is positive).

Statement 2: This is where I'm stuck. Can you just do this?

-2x = GT(3y) (from first equation, GT = greater than)
2x = LT(-3y) (divide both sides by -1 and flip the inequality)

2x+5y-20=0 (substitute LT(-3y) for 2x)
LT(-3y)+5y-20=0
LT(2y)=20
LT(y)=10
y> 10 (since y must be greater than 10, it must be positive, therefore sufficient?)

mdh
Top 
RonPurewal
 Post subject:
 Post Posted: Thu Jun 05, 2008 6:41 am 
Offline
ManhattanGMAT Staff


Posts: 7146
search before you post, please. thank you.
http://www.manhattangmat.com/forums/if- ... t3233.html

this is a particularly easy one to find: just type 2x 3y (or 2x 3y 5y, or ...) into the search box, and off you go. in other words, things like 2x and 3y count as 'words' in a search.
Top 
mdh3000
 Post subject:
 Post Posted: Sat Jun 07, 2008 11:34 am 
I guess you corrected the title of the post you're referring to after I searched for it, that's why I couldn't find it.

Anyways, thanks for your help Ron!!

mdh
Top 
RonPurewal
 Post subject:
 Post Posted: Mon Jun 09, 2008 2:36 am 
Offline
ManhattanGMAT Staff


Posts: 7146
mdh3000 wrote:
I guess you corrected the title of the post you're referring to after I searched for it, that's why I couldn't find it.

Anyways, thanks for your help Ron!!

mdh


no prob, it sometimes takes a bit of time to become expert at using the search box.

just remember that search-box 'words' can include alphanumeric strings (such as 2x and 5y) in addition to strings consisting strictly of letters.
just DON'T type negative signs into the search box; negative signs in a search string will be interpreted as "search for pages that DON'T contain this string".
Top 
Display posts from previous:  Sort by  
 
 Page 1 of 1 [ 4 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: