Is xy < 0 ? : GMAT Data Sufficiency (DS)
Check GMAT Club Decision Tracker for the Latest School Decision Releases http://gmatclub.com/AppTrack

 It is currently 24 Jan 2017, 08:19

# LIVE NOW:

How to Get Off the MBA Waitlist: YouTube Live with Personal MBA Coach  |  Click Here to Join the Session

### 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

# Is xy < 0 ?

Author Message
TAGS:

### Hide Tags

Moderator
Joined: 01 Sep 2010
Posts: 3097
Followers: 788

Kudos [?]: 6573 [2] , given: 1023

Is xy < 0 ? [#permalink]

### Show Tags

08 May 2012, 02:25
2
KUDOS
4
This post was
BOOKMARKED
00:00

Difficulty:

25% (medium)

Question Stats:

67% (01:47) correct 33% (01:06) wrong based on 285 sessions

### HideShow timer Statistics

Is xy < 0?

(1) 5|x| + |y| = 0
(2) |x| + 5|y| = 0
[Reveal] Spoiler: OA

_________________
VP
Joined: 24 Jul 2011
Posts: 1126
GMAT 1: 780 Q51 V48
GRE 1: 1540 Q800 V740
Followers: 124

Kudos [?]: 542 [0], given: 19

Re: Is xy < 0 ? [#permalink]

### Show Tags

08 May 2012, 08:34
Statement 1 => x = y = 0. Sufficient.
Statement 2 => x = y = 0. Sufficient.

Choice D.
_________________

GyanOne | Top MBA Rankings and MBA Admissions Blog

Premium MBA Essay Review|Best MBA Interview Preparation|Exclusive GMAT coaching

Get a FREE Detailed MBA Profile Evaluation | Call us now +91 98998 31738

Last edited by GyanOne on 09 May 2012, 02:08, edited 1 time in total.
Intern
Joined: 15 Jan 2012
Posts: 20
GMAT 1: 760 Q50 V44
GPA: 3.85
WE: Marketing (Computer Software)
Followers: 0

Kudos [?]: 8 [0], given: 2

Re: Is xy < 0 ? [#permalink]

### Show Tags

08 May 2012, 11:44
GyanOne wrote:
Statement 1 => |y|/|x| = -5 => x and y are of opposite signs => xy<0. Sufficient.
Statement 2 => |x|/|y| = -5 => x and y are of opposite signs => xy<0. Sufficient.

Choice D.

D as well,
(1) 5|x| + |y| = 0
When is a sum equal to zero? one is negative, one is positive. But || (absolute value?, not sure what is the English for it) can't be negative, thus both |x| an |y| should be equal to zero. This means xy clearly is not < 0, but equal to zero. Sufficient
(2) same thing for this option
Math Expert
Joined: 02 Sep 2009
Posts: 36625
Followers: 7106

Kudos [?]: 93646 [2] , given: 10583

Re: Is xy < 0 ? [#permalink]

### Show Tags

09 May 2012, 01:42
2
KUDOS
Expert's post
2
This post was
BOOKMARKED
GyanOne wrote:
Statement 1 => |y|/|x| = -5 => x and y are of opposite signs => xy<0. Sufficient.
Statement 2 => |x|/|y| = -5 => x and y are of opposite signs => xy<0. Sufficient.

Choice D.

That's not correct.

Is xy < 0?

(1) 5|x| + |y| = 0. Since absolute value is always non-negative then we have that the sum of two non-negative values (5|x| and |y|) is zero, which is only possible if each is zero --> x=y=0 --> xy=0. Sufficient.

(2) |x| + 5|y| = 0. The same here. Sufficient.

_________________
Intern
Joined: 07 May 2011
Posts: 42
GMAT 1: Q V
GMAT 2: Q V
Followers: 0

Kudos [?]: 18 [0], given: 11

Re: Is xy < 0 ? [#permalink]

### Show Tags

27 Nov 2012, 18:32
This was a good problem.

carcass wrote:
Is xy < 0?

(1) 5|x| + |y| = 0

(2) |x| + 5|y| = 0
GMAT Club Legend
Joined: 09 Sep 2013
Posts: 13542
Followers: 578

Kudos [?]: 163 [0], given: 0

Re: Is xy < 0 ? [#permalink]

### Show Tags

23 Sep 2014, 14:18
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________
Intern
Joined: 16 Oct 2012
Posts: 5
Followers: 0

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

Re: Is xy < 0 ? [#permalink]

### Show Tags

26 Sep 2014, 13:12
question is X and y are opposite sign?

stmt 1 : 5x=-y
x/y = - 5, x and y are opposite sign , sufficient.

stmt2L x=-5y, x/y = -5 , x and y are opposite sign , sufficient.

if x and y are same sign x/y will always be positive.
GMAT Club Legend
Joined: 09 Sep 2013
Posts: 13542
Followers: 578

Kudos [?]: 163 [0], given: 0

Re: Is xy < 0 ? [#permalink]

### Show Tags

13 Mar 2016, 09:50
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________
Math Revolution GMAT Instructor
Joined: 16 Aug 2015
Posts: 2626
GPA: 3.82
Followers: 174

Kudos [?]: 1461 [0], given: 0

Re: Is xy < 0 ? [#permalink]

### Show Tags

13 Mar 2016, 21:24
Forget conventional ways of solving math questions. In DS, Variable approach is the easiest and quickest way to find the answer without actually solving the problem. Remember equal number of variables and independent equations ensures a solution.

Is xy < 0?

In the original condition, there are 2 variables(x,y), which should match with the number of equations. So you need 2 equations. For 1) 1 equation, for 2) 1 equation, which is likely to make C the answer. When 1) & 2), 1)=2) -> x=y=0, which is no and sufficient.

 For cases where we need 2 more equations, such as original conditions with “2 variables”, or “3 variables and 1 equation”, or “4 variables and 2 equations”, we have 1 equation each in both 1) and 2). Therefore, there is 70% chance that C is the answer, while E has 25% chance. These two are the majority. In case of common mistake type 3,4, the answer may be from A, B or D but there is only 5% chance. Since C is most likely to be the answer using 1) and 2) separately according to DS definition (It saves us time). Obviously there may be cases where the answer is A, B, D or E.
_________________

MathRevolution: Finish GMAT Quant Section with 10 minutes to spare
The one-and-only World’s First Variable Approach for DS and IVY Approach for PS with ease, speed and accuracy.
Find a 10% off coupon code for GMAT Club members.
“Receive 5 Math Questions & Solutions Daily”
Unlimited Access to over 120 free video lessons - try it yourself

Re: Is xy < 0 ?   [#permalink] 13 Mar 2016, 21:24
Similar topics Replies Last post
Similar
Topics:
1 Is xy < 0? 3 14 Jan 2017, 08:00
2 Is xy < 0? 2 11 Jun 2016, 09:17
5 If xy > 0, is (xy)^2<√xy ? 3 29 Apr 2016, 02:53
If xy ≠ 0, is x/y < 0? 2 06 Oct 2014, 08:35
8 Is xy < 0 ? 12 04 Aug 2010, 14:17
Display posts from previous: Sort by