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

It is currently 20 Oct 2014, 17:24

Close

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

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

Is xy <0? 1. (x^3 * y^4)/(xy) <0 2. |x| -|y| < |x-y

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
Senior Manager
Senior Manager
avatar
Joined: 02 Mar 2004
Posts: 330
Location: There
Followers: 1

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

Is xy <0? 1. (x^3 * y^4)/(xy) <0 2. |x| -|y| < |x-y [#permalink] New post 15 May 2004, 16:30
00:00
A
B
C
D
E

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 0 sessions
Is xy <0?
1. (x^3 * y^4)/(xy) <0
2. |x| -|y| < |x-y|
Senior Manager
Senior Manager
avatar
Joined: 02 Feb 2004
Posts: 345
Followers: 1

Kudos [?]: 10 [0], given: 0

Re: DS-107 [#permalink] New post 15 May 2004, 17:18
hallelujah1234 wrote:
Is xy <0?
1. (x^3 * y^4)/(xy) <0
2. |x| -|y| < |x-y|



(x^3 * y^4)/(xy) <0

x^2 * y^3<0
y<0, x could go either way! insuff.


|x| -|y| < |x-y|
if, |x| -|y| = |x-y|, both x & y have same sign
for |x| -|y| < |x-y|, x must have greater abs. value than y. but it doesn't say what's their normal signs are. insuff.
it's E. :idea:
GMAT Club Legend
GMAT Club Legend
avatar
Joined: 15 Dec 2003
Posts: 4318
Followers: 23

Kudos [?]: 170 [0], given: 0

 [#permalink] New post 15 May 2004, 17:38
I would go with C

From 1) (x^3 * y^4)/(xy) < 0 --> x^2 * y^3 < 0
This means x can be either positive or negative but y HAS to be negative. So possible combination of x,y are:
(x=+) and (y=+) or
(x=-) and (y=+)
Insuff.

From 2) In order for lx-yl to be greater than left side, combinations have to be:
(x=+) and (y=-) or
(x=-) and (y=+)
Insuff.

From both combined, we can see that the only combination is when (x=-) and (y=+).
Therefore, xy < 0 is affirmative
_________________

Best Regards,

Paul

Senior Manager
Senior Manager
avatar
Joined: 02 Feb 2004
Posts: 345
Followers: 1

Kudos [?]: 10 [0], given: 0

 [#permalink] New post 15 May 2004, 17:48
Paul wrote:
I would go with C

From 1) (x^3 * y^4)/(xy) < 0 --> x^2 * y^3 < 0
This means x can be either positive or negative but y HAS to be negative. So possible combination of x,y are:
(x=+) and (y=+) or
(x=-) and (y=+)
Insuff.

From 2) In order for lx-yl to be greater than left side, combinations have to be:
(x=+) and (y=-) or
(x=-) and (y=+)
Insuff.

From both combined, we can see that the only combination is when (x=-) and (y=+).
Therefore, xy < 0 is affirmative


can you pls pick a number & prove it
GMAT Club Legend
GMAT Club Legend
avatar
Joined: 15 Dec 2003
Posts: 4318
Followers: 23

Kudos [?]: 170 [0], given: 0

 [#permalink] New post 15 May 2004, 18:19
Hmmm, I just realized I misinterpreted statement 1 as instances where the left side was > 0. It should have been < 0 but answer is still C

From 1) (x^3 * y^4)/(xy) < 0 --> x^2 * y^3 < 0
This means x can be either positive or negative but y HAS to be negative. So possible combination of x,y are:
(x=+) and (y=-) or
(x=-) and (y=-)
Insuff.

From 2) In order for lx-yl to be greater than left side, combinations have to be:
(x=+) and (y=-) or
(x=-) and (y=+)
Insuff.

From both combined, we can see that the only combination is when (x=+) and (y=-)

Therefore, xy < 0 is still affirmative
Let's pick numbers
x=2
y=-1
From 1) 2^2 * (-1)^3 = -4 which is < 0
From 2) l2l - l-1l < l2 - (-1)l --> 1 < 3
Both combined: 2*(-1) = -2 which is < 0 and question can be answered
y
_________________

Best Regards,

Paul

SVP
SVP
User avatar
Joined: 30 Oct 2003
Posts: 1798
Location: NewJersey USA
Followers: 4

Kudos [?]: 36 [0], given: 0

 [#permalink] New post 16 May 2004, 04:21
b) |x| - |y| < |x-y| only when both signs are same and neither of x and y is zero.
In anycase xy > 0
B is sufficient.
Manager
Manager
User avatar
Joined: 07 May 2004
Posts: 184
Location: Ukraine, Russia(part-time)
Followers: 2

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

Re: DS-107 [#permalink] New post 16 May 2004, 09:42
hallelujah1234 wrote:
Is xy <0?
1. (x^3 * y^4)/(xy) <0
2. |x| -|y| < |x-y|


B is the answer.

2 is sufficient to guarantee xy < |xy| => xy < 0.

1 is not.
Senior Manager
Senior Manager
avatar
Joined: 02 Mar 2004
Posts: 330
Location: There
Followers: 1

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

Re: DS-107 [#permalink] New post 16 May 2004, 09:57
Emmanuel wrote:
hallelujah1234 wrote:
Is xy <0?
1. (x^3 * y^4)/(xy) <0
2. |x| -|y| < |x-y|


B is the answer.

2 is sufficient to guarantee xy < |xy| => xy < 0.

1 is not.



x= 1; y = -2; xy < 0; |1|-|-2| < |1-(-2)|
x = -1; y = -2; xy > 0; |-1|-|-2| < |-1-(-2)|

Insufficient.

E is the answer

Last edited by hallelujah1234 on 17 May 2004, 08:29, edited 1 time in total.
Manager
Manager
User avatar
Joined: 07 May 2004
Posts: 184
Location: Ukraine, Russia(part-time)
Followers: 2

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

Re: DS-107 [#permalink] New post 16 May 2004, 10:01
hallelujah1234 wrote:
x= 1; y = -2; xy < 0; |1|-|-2| < |1-(-2)|
x = -1; y = -2; xy > 0; |-1|-|-2| < |-1-(-2)|

Insufficient.


Yeah, you're right, I'm wrong. I used wrong equivalence

|x|-|y|<|x-y| <=> (|x|-|y|)^2 < (x-y)^2!!!
Re: DS-107   [#permalink] 16 May 2004, 10:01
    Similar topics Author Replies Last post
Similar
Topics:
Is xy < 0? 1). (X^3 * Y^5)/ (X*Y^2) <0 2). |X| - |y| rampuria 5 27 Oct 2008, 08:14
Is xy < 0? 1). (X^3 * Y^5)/ (X*Y^2) <0 2). |X| - |y| vshaunak@gmail.com 5 20 May 2007, 04:54
Is xy < 0? 1). (X^3 * Y^5)/ (X*Y^2) <0 2). /X/ - /y/ joemama142000 1 25 Apr 2006, 09:09
Is xy < 0? 1). (X^3 * Y^5)/ (X*Y^2) <0 2). /X/ - /y/ Ethan 4 24 Apr 2006, 11:44
Is xy <0? 1). x^3y^4/xy <0 2). |x| - |y| < |x-y| crackets 6 26 Oct 2004, 09:25
Display posts from previous: Sort by

Is xy <0? 1. (x^3 * y^4)/(xy) <0 2. |x| -|y| < |x-y

  Question banks Downloads My Bookmarks Reviews Important topics  


GMAT Club MBA Forum Home| About| Privacy Policy| Terms and Conditions| GMAT Club Rules| Contact| Sitemap

Powered by phpBB © phpBB Group and phpBB SEO

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®.