It is currently 23 Nov 2017, 02:29

### 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

# If x and y are positive, what is the value of x-y? 1) (X^2 -

Author Message
Current Student
Joined: 03 Dec 2007
Posts: 83

Kudos [?]: 6 [0], given: 0

Schools: NYU STERN
If x and y are positive, what is the value of x-y? 1) (X^2 - [#permalink]

### Show Tags

29 Dec 2008, 11:26
00:00

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 100% (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 x and y are positive, what is the value of x-y?

1) (X^2 - Y^2) / (X+Y) = 4

2) X+Y = 7

I was trying to do this fast and thought oh 2 equations 2 variables - but you only need statement 1 to solve this and not sure why. How would you do this fast?

Kudos [?]: 6 [0], given: 0

Current Student
Joined: 13 May 2008
Posts: 141

Kudos [?]: 25 [1], given: 6

Schools: LBS
Re: Yet another DS Question I can't solve [#permalink]

### Show Tags

29 Dec 2008, 11:40
1
KUDOS
(X^2 - Y^2) / (X+Y) = 4

(X^2 - Y^2) = 4* (X+Y)

(x-y)*(x+y) = 4* (X+Y)

(x-y) = 4

Kudos [?]: 25 [1], given: 6

Manager
Joined: 15 Apr 2008
Posts: 164

Kudos [?]: 12 [0], given: 1

Re: Yet another DS Question I can't solve [#permalink]

### Show Tags

29 Dec 2008, 14:10
hardaway7 wrote:
If x and y are positive, what is the value of x-y?

1) (X^2 - Y^2) / (X+Y) = 4

2) X+Y = 7

I was trying to do this fast and thought oh 2 equations 2 variables - but you only need statement 1 to solve this and not sure why. How would you do this fast?

this is just application of a formula. x^2-y^2= (x-y)(x+y)

Kudos [?]: 12 [0], given: 1

Current Student
Joined: 03 Dec 2007
Posts: 83

Kudos [?]: 6 [0], given: 0

Schools: NYU STERN
Re: Yet another DS Question I can't solve [#permalink]

### Show Tags

29 Dec 2008, 14:32
thanks all - this was fairly easy- not sure why I was having trouble!!

Kudos [?]: 6 [0], given: 0

Re: Yet another DS Question I can't solve   [#permalink] 29 Dec 2008, 14:32
Display posts from previous: Sort by

# If x and y are positive, what is the value of x-y? 1) (X^2 -

 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®.