It is currently 25 Jun 2017, 00:35

### 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

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

# Events & Promotions

###### Events & Promotions in June
Open Detailed Calendar

# What is the value of x^2 + y^2? (1) x^2 + y^2 = 2xy +1 (2)

Author Message
Senior Manager
Joined: 25 Nov 2006
Posts: 332
Schools: St Gallen, Cambridge, HEC Montreal
What is the value of x^2 + y^2? (1) x^2 + y^2 = 2xy +1 (2) [#permalink]

### Show Tags

28 Jan 2009, 11:57
00:00

Difficulty:

(N/A)

Question Stats:

50% (03:25) correct 50% (02:11) wrong based on 0 sessions

### HideShow timer Statistics

This topic is locked. If you want to discuss this question please re-post it in the respective forum.

What is the value of x^2 + y^2?

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

(2) x^2 + y^2 = 4 - 2xy
Senior Manager
Joined: 30 Nov 2008
Posts: 489
Schools: Fuqua

### Show Tags

28 Jan 2009, 12:22
IMO C.

From Stmt 1, we can derive, x^2+ y^2-2xy = 1 ==> cannot say the value for x^2 + y^2 with this information. In Sufficient.
From Stmt 2, we can derive, x^2+ y^2+2xy = 4 ==> cannot say the value for x^2 + y^2 with this information. In Sufficient.

Now combining both the equations, two unknowns and two equations, definitely we can solve both the eqs to get the value of x and y from which we can get the value x^2 + y^2.

Well the value of x^2 + y^2 = 5/2.
Re: DS question   [#permalink] 28 Jan 2009, 12:22
Display posts from previous: Sort by