It is currently 23 Feb 2018, 02:48

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

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

If 0<x<y, what is the value of (x+y)^2 / (x-y)^2 ? 1.

 post reply Question banks Downloads My Bookmarks Reviews Important topics
Author Message
Intern
Joined: 18 Jul 2008
Posts: 34
If 0<x<y, what is the value of (x+y)^2 / (x-y)^2 ? 1. [#permalink]

Show Tags

12 Aug 2008, 11:29
00:00

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 1 sessions

HideShow timer Statistics

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

If 0<x<y, what is the value of (x+y)^2 / (x-y)^2 ?
1. x^2 + y^2 = 3xy
2. xy = 3
SVP
Joined: 07 Nov 2007
Posts: 1789
Location: New York
Re: one more: gmatperp DS [#permalink]

Show Tags

12 Aug 2008, 11:35
mba9now wrote:
If 0<x<y, what is the value of (x+y)^2 / (x-y)^2 ?
1. x^2 + y^2 = 3xy
2. xy = 3

(x+y)^2 / (x-y)^2 = ( x^2 + y^2+2xy )/( x^2 + y^2-2xy )

1) suffcieint
( x^2 + y^2+2xy )/( x^2 + y^2-2xy )
= 5xy/xy=5
2) ( x^2 + y^2+2xy )/( x^2 + y^2-2xy ) = (x^2 + y^2+6)/( x^2 + y^2-6)
two variable and only one equation xy=3 and we need to find values both variables.
Not suffcieint

A.

What is OA
_________________

Your attitude determines your altitude
Smiling wins more friends than frowning

SVP
Joined: 30 Apr 2008
Posts: 1863
Location: Oklahoma City
Schools: Hard Knocks
Re: one more: gmatperp DS [#permalink]

Show Tags

12 Aug 2008, 11:49
A

#1

$$\frac{(x+y)^2}{(x-y)^2} =$$

$$\frac{(x+y)(x+y)}{(x-y)(x-y)}=$$

$$\frac{x^2+2xy+y^2}{x^2-2xy+y^2}$$

$$\frac{x^2+y^2+2xy}{x^2+y^2-2xy}$$

Now substitute $$3xy$$ for $$x^2 + y^2$$ because $$x^2 + y^2 = 3xy$$

$$\frac{3xy+2xy}{3xy-2xy}$$

$$\frac{5xy}{xy} = 5$$ SUFFICIENT

$$\frac{x^2+y^2+2xy}{x^2+y^2-2xy}$$

Now substitute 3 for xy:

$$\frac{x^2+y^2+2(3)}{x^2+y^2-2(3)}$$

$$\frac{x^2+y^2+6}{x^2+y^2-6}$$

It can't be simplieifed any further and we don't know values of x or y. INSUFFICIENT.

mba9now wrote:
If 0<x<y, what is the value of (x+y)^2 / (x-y)^2 ?
1. x^2 + y^2 = 3xy
2. xy = 3

_________________

------------------------------------
J Allen Morris
**I'm pretty sure I'm right, but then again, I'm just a guy with his head up his a.

GMAT Club Premium Membership - big benefits and savings

Manager
Joined: 23 Apr 2008
Posts: 85
Re: one more: gmatperp DS [#permalink]

Show Tags

13 Aug 2008, 22:30
mba9now wrote:
If 0<x<y, what is the value of (x+y)^2 / (x-y)^2 ?
1. x^2 + y^2 = 3xy
2. xy = 3

A.
(x+y)^2=x^2+y^2+2xy
(x-y)^2=x^2+y^2-2xy

on simplification..we are left with 5xy/xy => 5

A IS SUFFICIENT

B.WE CANT FIND THE VALUE WITH THIS INFORMATION

ANSWER A
Re: one more: gmatperp DS   [#permalink] 13 Aug 2008, 22:30
Display posts from previous: Sort by

If 0<x<y, what is the value of (x+y)^2 / (x-y)^2 ? 1.

 post reply Question banks Downloads My Bookmarks Reviews Important topics

 Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne 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®.