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

It is currently 01 Sep 2015, 14:48
GMAT Club Tests

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

What is the value of xy?

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
Intern
Intern
avatar
Joined: 19 Dec 2006
Posts: 7
Followers: 0

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

What is the value of xy? [#permalink] New post 22 Mar 2007, 12:28
00:00
A
B
C
D
E

Difficulty:

(N/A)

Question Stats:

100% (05:39) correct 0% (00:00) wrong based on 0 sessions
This topic is locked. If you want to discuss this question please re-post it in the respective forum.

Can anyone help me make sense of this one? Thanks in advance for your help..

What is the value of xy?

(1) (x + y)^2 = 37
(2) (x - y)^2 = 17

I came up with 'E', but after checking the answer, it was "C". Can someone please explain why?
Manager
Manager
User avatar
Joined: 02 Jan 2007
Posts: 208
Followers: 2

Kudos [?]: 5 [0], given: 0

 [#permalink] New post 22 Mar 2007, 12:47
Here's my solution:

1) (x + y)^2 = 37
x^2 + y^2 +2xy = 37

One equation and 2 variables - insuff.

2) (x - y)^2 = 17
x^2 + y^2 - 2xy = 17
One equation and 2 variables - insuff.

working with 1) & 2)
1) - 2) = 20 (37 - 17)
x^2 + y^2 +2xy - ( x^2 + y^2 - 2xy ) = 20
solve and you get xy = 5...............suff. so C
Intern
Intern
avatar
Joined: 19 Dec 2006
Posts: 7
Followers: 0

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

 [#permalink] New post 23 Mar 2007, 06:59
Vikramjit_01

Thank you very much. After going over it once more and seeing your explanation, it's clearer now, much appreciated!
  [#permalink] 23 Mar 2007, 06:59
Display posts from previous: Sort by

What is the value of xy?

  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®.