Find all School-related info fast with the new School-Specific MBA Forum

It is currently 17 Sep 2014, 01:51

Close

GMAT Club Daily Prep

Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track
Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

Is x2 y2 a positive number? (1) x y is a positive number.

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
Manager
Manager
avatar
Joined: 07 Jan 2008
Posts: 87
Followers: 2

Kudos [?]: 28 [0], given: 1

Is x2 y2 a positive number? (1) x y is a positive number. [#permalink] New post 02 Oct 2008, 05:47
00:00
A
B
C
D
E

Difficulty:

(N/A)

Question Stats:

100% (01:18) correct 0% (00:00) wrong based on 0 sessions
24. Is x2 – y2 a positive number?
(1) x – y is a positive number.
(2) x + y is a positive number.

I chose (A) for this one. If x - y > 0 then x > y. So x2-y2 will be a +ve number.

the OA is C though x2 - y2 = (x+y)(x-y)
Manager
Manager
avatar
Joined: 22 Sep 2008
Posts: 124
Followers: 1

Kudos [?]: 37 [0], given: 0

Re: 1000 DS Section 1 24 [#permalink] New post 03 Oct 2008, 06:47
x = 2
y = -3

x-y = 2 - -3 = 5 which is positive number now x^2 - y^2 = 4 - 9 = -5 which is not positive number :)

B alone is also not suff.

A + B is sufficient
Senior Manager
Senior Manager
avatar
Joined: 05 Oct 2008
Posts: 273
Followers: 3

Kudos [?]: 44 [0], given: 22

GMAT Tests User
Re: 1000 DS Section 1 24 [#permalink] New post 05 Oct 2008, 11:23
Does anyone here know how to get access to the 1000 DS questions?
Senior Manager
Senior Manager
avatar
Joined: 31 Jul 2008
Posts: 309
Followers: 1

Kudos [?]: 18 [0], given: 0

GMAT Tests User
Re: 1000 DS Section 1 24 [#permalink] New post 05 Oct 2008, 12:27
C

for x+y is +ve , imagine y as 3 and x as -2 :: -> (-2-3)(-2+3)
Re: 1000 DS Section 1 24   [#permalink] 05 Oct 2008, 12:27
    Similar topics Author Replies Last post
Similar
Topics:
1) x^2 + y^2 > Z^2 X^2, Y^2, Z^2 are always positive Aleehsgonji 6 23 Jul 2009, 19:29
1 Is x a negative number? (1) x2 is a positive number. (2) x prinits 12 31 May 2009, 06:23
Is x2 y2 a positive number? (1) x y is a positive number. amitdgr 5 02 Oct 2008, 09:36
Is x2 y2 a positive number? (1) x y is a positive number. SunShine 2 26 Jan 2006, 01:26
Is x^2 y^2 a positive number? (1) x y is a positive number. MA 9 08 Mar 2005, 22:23
Display posts from previous: Sort by

Is x2 y2 a positive number? (1) x y is a positive number.

  Question banks Downloads My Bookmarks Reviews Important topics  


GMAT Club MBA Forum Home| About| Privacy Policy| Terms and Conditions| GMAT Club Rules| Contact| Sitemap

Powered by phpBB © phpBB Group and phpBB SEO

Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.