It is currently 23 Mar 2018, 00:19

### 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 x not equals to -y, is (x-y)/(x+y)>1? 1. x >0 2.

 post reply Question banks Downloads My Bookmarks Reviews Important topics
Author Message
Manager
Status: Stanford GSB
Joined: 02 Jun 2008
Posts: 93
If x not equals to -y, is (x-y)/(x+y)>1? 1. x >0 2. [#permalink]

### Show Tags

12 Jan 2009, 03:06
00:00

Difficulty:

(N/A)

Question Stats:

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

### HideShow timer Statistics

If x not equals to -y, is (x-y)/(x+y)>1?
1. x >0
2. y< 0

--== Message from GMAT Club Team ==--

This is not a quality discussion. It has been retired.

If you would like to discuss this question please re-post it in the respective forum. Thank you!

To review the GMAT Club's Forums Posting Guidelines, please follow these links: Quantitative | Verbal Please note - we may remove posts that do not follow our posting guidelines. Thank you.
Intern
Joined: 16 Jun 2008
Posts: 17
Location: Kiev, Ukraine
Schools: INSEAD
Re: DS-Inequality GMATprep [#permalink]

### Show Tags

12 Jan 2009, 06:21
(x-y)/(x+y)>1 means that (x-y)>(x+y)

We solve this equation and get 2y<0, so y<0. Second assumption gives us exactly this condition, so second assumption is enough to answer that (x-y)/(x+y)>1.

Answer is B.
Manager
Status: Stanford GSB
Joined: 02 Jun 2008
Posts: 93
Re: DS-Inequality GMATprep [#permalink]

### Show Tags

13 Jan 2009, 14:39
OA is E.
Can anyone suggest how to tackle this one?
SVP
Joined: 29 Aug 2007
Posts: 2452
Re: DS-Inequality GMATprep [#permalink]

### Show Tags

13 Jan 2009, 20:48
sandipchowdhury wrote:
If x not equals to -y, is (x-y)/(x+y)>1?
1. x >0
2. y< 0

I would suggest pluging in:

1: x > 0 but y? could be -ve 0 or +ve.

i. If y = 0, (x-y)/(x+y) = 1.
ii. If y > x > 0, (x-y)/(x+y) < 0.
iii. If x > y > 0, (x-y)/(x+y) < 1.
iv. If y < 0 and lyl < x, (x-y)/(x+y) > 1.
iv. If y < 0 and lyl > x, (x-y)/(x+y) < 0.

2: y < 0 but x ? could be -ve 0 or +ve. same as in 1.

i. If x = 0, (x-y)/(x+y) = -1.
ii. If x > 0 and x > lyl, (x-y)/(x+y) > 1.
iii. If x > 0 and x < lyl, (x-y)/(x+y) < 0.
iv. If 0 < x < y, (x-y)/(x+y) > 0 but <1.
v. If 0 < y < x, (x-y)/(x+y) > 0 but <1.

1&2:

i. If lyl < x, (x-y)/(x+y) > 1.
ii. If lyl > x, (x-y)/(x+y) < 0.

So -- E.

PS: Appreciate you for pointing out typos, if any.
_________________

Verbal: http://gmatclub.com/forum/new-to-the-verbal-forum-please-read-this-first-77546.html
Math: http://gmatclub.com/forum/new-to-the-math-forum-please-read-this-first-77764.html
Gmat: http://gmatclub.com/forum/everything-you-need-to-prepare-for-the-gmat-revised-77983.html

GT

Manager
Status: Stanford GSB
Joined: 02 Jun 2008
Posts: 93
Re: DS-Inequality GMATprep [#permalink]

### Show Tags

13 Jan 2009, 22:54
is there a shorter way to solve this?
Can we simplify the equation before pluging in?
SVP
Joined: 29 Aug 2007
Posts: 2452
Re: DS-Inequality GMATprep [#permalink]

### Show Tags

16 Jan 2009, 11:10
Thanks cowalko, who generously pointed a mistake.
I knew I was missing something while doing this. My intuition!

GT

cowalko wrote:
Subject: DS-Inequality GMATprep

GMAT TIGER wrote:
sandipchowdhury wrote:
If x not equals to -y, is (x-y)/(x+y)>1?
1. x >0
2. y< 0

I would suggest pluging in:

1: x > 0 but y? could be -ve 0 or +ve.

i. If y = 0, (x-y)/(x+y) = 1.
ii. If y > x > 0, (x-y)/(x+y) < 0.
iii. If x > y > 0, (x-y)/(x+y) < 1.
iv. If y < 0 and lyl < x, (x-y)/(x+y) > 1.
iv. If y < 0 and lyl > x, (x-y)/(x+y) < 0.

2: y < 0 but x ? could be -ve 0 or +ve. same as in 1.

i. If x = 0, (x-y)/(x+y) = -1.
ii. If x > 0 and x > lyl, (x-y)/(x+y) > 1.
iii. If x > 0 and x < lyl, (x-y)/(x+y) < 0.
iv. If 0 < x < y, (x-y)/(x+y) > 0 but <1.
v. If 0 < y < x, (x-y)/(x+y) > 0 but <1.

1&2:

i. If lyl < x, (x-y)/(x+y) > 1.
ii. If lyl > x, (x-y)/(x+y) < 0.

So -- E.

PS: Appreciate you for pointing out typos, if any.

Just one note not affecting the solution: Neither y nor x can be 0, because the problem says that x does not equal -y. X only equals -Y when x and y are 0

_________________

Verbal: http://gmatclub.com/forum/new-to-the-verbal-forum-please-read-this-first-77546.html
Math: http://gmatclub.com/forum/new-to-the-math-forum-please-read-this-first-77764.html
Gmat: http://gmatclub.com/forum/everything-you-need-to-prepare-for-the-gmat-revised-77983.html

GT

GMAT Tutor
Joined: 24 Jun 2008
Posts: 1346
Re: DS-Inequality GMATprep [#permalink]

### Show Tags

16 Jan 2009, 14:47
nlutsenko wrote:
(x-y)/(x+y)>1 means that (x-y)>(x+y)

We solve this equation and get 2y<0, so y<0. Second assumption gives us exactly this condition, so second assumption is enough to answer that (x-y)/(x+y)>1.

Answer is B.

You can't simplify as you've done: you multiplied both sides of the inequality by x+y, which you can't do, because you don't know if x+y is negative or positive. If x+y is negative, you'd need to reverse the inequality.

sandipchowdhury wrote:
is there a shorter way to solve this?
Can we simplify the equation before pluging in?

Yes, the question can be answered quickly. Even using both statements, on the left side of the inequality, the numerator is certainly positive, but the denominator could be positive and could be negative. So the left side of the inequality could be positive or negative. Since it can be negative, and it can also clearly be larger than 1 (choose x = 2, y = -1), the statements together are insufficient. So E.
_________________

GMAT Tutor in Toronto

If you are looking for online GMAT math tutoring, or if you are interested in buying my advanced Quant books and problem sets, please contact me at ianstewartgmat at gmail.com

Manager
Status: Stanford GSB
Joined: 02 Jun 2008
Posts: 93
Re: DS-Inequality GMATprep [#permalink]

### Show Tags

16 Jan 2009, 22:20
Thanks Ian. Good thinking.

--== Message from GMAT Club Team ==--

This is not a quality discussion. It has been retired.

If you would like to discuss this question please re-post it in the respective forum. Thank you!

To review the GMAT Club's Forums Posting Guidelines, please follow these links: Quantitative | Verbal Please note - we may remove posts that do not follow our posting guidelines. Thank you.
Re: DS-Inequality GMATprep   [#permalink] 16 Jan 2009, 22:20
Display posts from previous: Sort by

# If x not equals to -y, is (x-y)/(x+y)>1? 1. x >0 2.

 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®.