Find all School-related info fast with the new School-Specific MBA Forum

 It is currently 29 Aug 2016, 20:40

### 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| = |y| and xy < 0, which of the following must be true

Author Message
TAGS:

### Hide Tags

Manager
Joined: 29 Mar 2010
Posts: 141
Location: United States
GMAT 1: 590 Q28 V38
GPA: 2.54
WE: Accounting (Hospitality and Tourism)
Followers: 1

Kudos [?]: 100 [3] , given: 16

If |x| = |y| and xy < 0, which of the following must be true [#permalink]

### Show Tags

21 Dec 2013, 13:10
3
KUDOS
8
This post was
BOOKMARKED
00:00

Difficulty:

5% (low)

Question Stats:

85% (01:45) correct 15% (01:11) wrong based on 566 sessions

### HideShow timer Statistics

If |x| = |y| and xy < 0, which of the following must be true?

A. xy^2 > 0

B. yx^2 > 0

C. x + y = 0

D. x/y +1=2

E. 1/x + 1/y = 1/2]
[Reveal] Spoiler: OA

_________________

4/28 GMATPrep 42Q 36V 640

Last edited by Bunuel on 22 Dec 2013, 04:56, edited 1 time in total.
Edited the question and added the OA.
Joined: 10 Oct 2013
Posts: 36
Location: India
Concentration: Technology, Entrepreneurship
GMAT 1: 700 Q49 V35
GMAT 2: 750 Q51 V40
GPA: 3.85
WE: Research (Telecommunications)
Followers: 2

Kudos [?]: 17 [0], given: 38

Re: If |x|=|y| and xy<0, which of the following must be true? [#permalink]

### Show Tags

21 Dec 2013, 13:16
1. x and y have same magnitude, |x| = |y|
2. They have opposite signs xy<0
Implies x = -y or y = -x
So C: x+y =0
Manager
Status: folding sleeves up
Joined: 26 Apr 2013
Posts: 154
Location: India
Concentration: Finance, Strategy
GMAT 1: 530 Q39 V23
GMAT 2: 560 Q42 V26
GPA: 3.5
WE: Consulting (Computer Hardware)
Followers: 1

Kudos [?]: 65 [0], given: 39

Re: If |x| = |y| and xy < 0, which of the following must be true [#permalink]

### Show Tags

25 Mar 2014, 12:49
|x| = |y| this means when they come out of Mod they will be positive----->eq1

xy < 0 this means multiplication of both values is less than zero or better to be read as -ve. Hence either x or y is -ve---->eq2

so combining eq1 and eq 2
we have

x + (-y) = 0 (because of eq 1)
(-x) + y = 0 (again because of eq 1)

Hence C
Intern
Joined: 02 Jan 2015
Posts: 21
Followers: 0

Kudos [?]: 7 [2] , given: 15

Re: If |x| = |y| and xy < 0, which of the following must be true [#permalink]

### Show Tags

26 Jan 2015, 19:27
2
KUDOS
If |x| = |y|

then x^2=y^2
=>x^2-y^2=0
=>(x+y)(x-y)=0
(x+y)=0

EMPOWERgmat Instructor
Status: GMAT Assassin/Co-Founder
Affiliations: EMPOWERgmat
Joined: 19 Dec 2014
Posts: 7214
Location: United States (CA)
GMAT 1: 800 Q51 V49
GRE 1: 340 Q170 V170
Followers: 315

Kudos [?]: 2133 [1] , given: 161

Re: If |x| = |y| and xy < 0, which of the following must be true [#permalink]

### Show Tags

27 Jan 2015, 00:33
1
KUDOS
Expert's post
Hi All,

This question can be solved by TESTing VALUES. You can gain a nice shortcut if you realize that you can TEST two pairs of VALUES at the same time.

We're told that |X|=|Y| and that XY < 0. This means that one variable is NEGATIVE and the other is POSITIVE, but it doesn't matter which is which. We're asked which of the following answer MUST be true (which is the same as asking "which is ALWAYS TRUE no matter how many different examples you can come up with?")

Let's TEST....
X = 2
Y = -2

and
X = -2
Y = 2

Answer A: X(Y^2) > 0 If X = -2, Y = 2, then this is NOT TRUE.

Answer B: Y(X^2) > 0 If Y = -2, X = 2, then this is NOT TRUE.

Answer C: X + Y = 0 (2) + (-2) = 0 This IS TRUE.

Answer D: X/Y + 1 = 2 2/-2 + 1 is NOT = 2. This is NOT TRUE

Answer E: 1/X + 1/Y = 1/2 1/2 + 1/-2 is NOT = 1/2 This is NOT TRUE

[Reveal] Spoiler:
C

GMAT assassins aren't born, they're made,
Rich
_________________

# Rich Cohen

Co-Founder & GMAT Assassin

# Special Offer: Save $75 + GMAT Club Tests 60-point improvement guarantee www.empowergmat.com/ ***********************Select EMPOWERgmat Courses now include ALL 6 Official GMAC CATs!*********************** Intern Joined: 14 Oct 2014 Posts: 19 Followers: 0 Kudos [?]: 4 [0], given: 16 if |x|=|y| and xy < 0, which of the following must be true? [#permalink] ### Show Tags 11 Mar 2015, 21:09 if |x|=|y| and xy < 0, which of the following must be true? A) xy^2 >0 B) x^2y > 0 C) x + y = 0 D) x/y + 1 = 2 E) 1/x +1/y = 1/2 Last edited by zatspeed on 11 Mar 2015, 23:02, edited 1 time in total. Veritas Prep GMAT Instructor Joined: 16 Oct 2010 Posts: 6838 Location: Pune, India Followers: 1929 Kudos [?]: 11980 [1] , given: 221 Re: if |x|=|y| and xy < 0, which of the following must be true? [#permalink] ### Show Tags 11 Mar 2015, 22:03 1 This post received KUDOS Expert's post zatspeed wrote: if |x| |y| and xy < 0, which of the following must be true? A) xy^2 >0 B) x^2y > 0 C) x + y = 0 D) x/y + 1 = 2 E) 1/x +1/y = 1/2 I am assuming the question is "If |x| = |y| and xy < 0, which of the following must be true?" The absolute values of x and y should be the same. But one of x and y should be negative and the other should be positive so that xy < 0. Put x = 1, y = -1 and then x = -1, y = 1 in the options to see which holds since the correct option should hold for all appropriate values of x and y. A) xy^2 >0 Will not hold for x = -1, y = 1 B) x^2y > 0 Will not hold for x = 1, y = -1 C) x + y = 0 Will hold for both. Hold it. D) x/y + 1 = 2 Will not hold. E) 1/x +1/y = 1/2 Will not hold. Answer (C) _________________ Karishma Veritas Prep | GMAT Instructor My Blog Get started with Veritas Prep GMAT On Demand for$199

Veritas Prep Reviews

EMPOWERgmat Instructor
Status: GMAT Assassin/Co-Founder
Affiliations: EMPOWERgmat
Joined: 19 Dec 2014
Posts: 7214
Location: United States (CA)
GMAT 1: 800 Q51 V49
GRE 1: 340 Q170 V170
Followers: 315

Kudos [?]: 2133 [0], given: 161

Re: if |x|=|y| and xy < 0, which of the following must be true? [#permalink]

### Show Tags

11 Mar 2015, 22:45
zatspeed wrote:
if |x| |y| and xy < 0, which of the following must be true?

A) xy^2 >0
B) x^2y > 0
C) x + y = 0
D) x/y + 1 = 2
E) 1/x +1/y = 1/2

Hi zatspeed,

In the original prompt (and in the title) is there supposed to be an "=" between |X| and |Y|? Karishma's explanation implies that there should be one there, but your post doesn't currently include that information.

GMAT assassins aren't born, they're made,
Rich
_________________

# Rich Cohen

Co-Founder & GMAT Assassin

# Special Offer: Save \$75 + GMAT Club Tests

60-point improvement guarantee
www.empowergmat.com/

***********************Select EMPOWERgmat Courses now include ALL 6 Official GMAC CATs!***********************

Intern
Joined: 14 Oct 2014
Posts: 19
Followers: 0

Kudos [?]: 4 [0], given: 16

Re: if |x|=|y| and xy < 0, which of the following must be true? [#permalink]

### Show Tags

11 Mar 2015, 23:01
Sorry about that, not sure why the half the data goes missing after I post it. Will update it.
Math Expert
Joined: 02 Sep 2009
Posts: 34496
Followers: 6297

Kudos [?]: 79883 [0], given: 10022

Re: If |x| = |y| and xy < 0, which of the following must be true [#permalink]

### Show Tags

12 Mar 2015, 06:25
zatspeed wrote:
if |x|=|y| and xy < 0, which of the following must be true?

A) xy^2 >0
B) x^2y > 0
C) x + y = 0
D) x/y + 1 = 2
E) 1/x +1/y = 1/2

___________
Merging similar topics.
_________________
GMAT Club Legend
Joined: 09 Sep 2013
Posts: 11133
Followers: 511

Kudos [?]: 134 [0], given: 0

Re: If |x| = |y| and xy < 0, which of the following must be true [#permalink]

### Show Tags

08 Jun 2016, 01:43
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.
_________________
Re: If |x| = |y| and xy < 0, which of the following must be true   [#permalink] 08 Jun 2016, 01:43
Similar topics Replies Last post
Similar
Topics:
If x < 0 and y is not equal to 0, which of the following must be true? 2 24 Aug 2016, 04:53
3 If |x| = |y| and xy = 0, which of the following must be true? 1 22 Jan 2016, 12:51
7 If x < 0, which of the following must be true? 7 03 Dec 2014, 08:19
3 If x-y=8, which of the following must be true? 5 17 Feb 2011, 18:08
6 If x^4*y < 0 and x*y^4 > 0 which of the following must be true? 5 02 Jul 2010, 23:42
Display posts from previous: Sort by