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

It is currently 14 Jul 2014, 08:19

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

ds: Is X > Y?

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
Director
Director
avatar
Joined: 11 Jun 2007
Posts: 649
Followers: 3

Kudos [?]: 28 [0], given: 0

GMAT Tests User
ds: Is X > Y? [#permalink] New post 10 Dec 2007, 15:28
1
This post was
BOOKMARKED
00:00
A
B
C
D
E

Difficulty:

  5% (low)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 0 sessions
Is X > Y?

(1) sqrt(X) > Y
(2) X^3 > Y

Do we consider sqrt(X) to be +ve?
Intern
Intern
User avatar
Joined: 01 Dec 2007
Posts: 32
Followers: 0

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

Re: ds: Is X > Y? [#permalink] New post 10 Dec 2007, 15:46
eyunni wrote:
Is X > Y?

(1) sqrt(X) > Y
(2) X^3 > Y

Do we consider sqrt(X) to be +ve?


C

1) NS because x>y is true if x is 4 but not true if x is 1/4

2) NS because x>y is true if x is 2 but not true if x is -1/2

1&2 Sufficient - after plugging in 2 and 1/4.

1) says that x is postive so no need to test negative numbers.
Director
Director
avatar
Joined: 11 Jun 2007
Posts: 649
Followers: 3

Kudos [?]: 28 [0], given: 0

GMAT Tests User
 [#permalink] New post 10 Dec 2007, 19:28
:?
Manager
Manager
avatar
Joined: 01 Nov 2007
Posts: 83
Followers: 0

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

 [#permalink] New post 10 Dec 2007, 20:48
Yes - 1 makes X positive

solutions for sqrt a^2 can be +/- a but a^2 (in this case X) is always a positive number

Someone correct me if I'm wrong
Director
Director
avatar
Joined: 09 Aug 2006
Posts: 767
Followers: 1

Kudos [?]: 41 [0], given: 0

GMAT Tests User
Re: ds: Is X > Y? [#permalink] New post 11 Dec 2007, 03:15
eyunni wrote:
Is X > Y?

(1) sqrt(X) > Y
(2) X^3 > Y

Do we consider sqrt(X) to be +ve?


Rule that comes out of this: If sqrt(x) > y and x^3 >y then x > y.
Director
Director
avatar
Joined: 11 Jun 2007
Posts: 649
Followers: 3

Kudos [?]: 28 [0], given: 0

GMAT Tests User
 [#permalink] New post 11 Dec 2007, 07:20
I am still not convinced. Can someone please answer my question?

(1) sqrt(X) > Y

Is sqrt(X) +ve in this question?
Expert Post
CEO
CEO
User avatar
Joined: 17 Nov 2007
Posts: 3600
Concentration: Entrepreneurship, Other
Schools: Chicago (Booth) - Class of 2011
GMAT 1: 750 Q50 V40
Followers: 346

Kudos [?]: 1666 [0], given: 354

GMAT ToolKit User GMAT Tests User Premium Member
 [#permalink] New post 11 Dec 2007, 08:05
Expert's post
√X > Y is true only when √X is defined. Therefore x e (0,+∞]
Intern
Intern
avatar
Joined: 25 Nov 2007
Posts: 40
Followers: 0

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

 [#permalink] New post 11 Dec 2007, 08:06
eyunni wrote:
I am still not convinced. Can someone please answer my question?

(1) sqrt(X) > Y

Is sqrt(X) +ve in this question?


sqrt(X) +ve if x is positive and -ve if x is negative..

C is the answer. Whats the OA??
Director
Director
avatar
Joined: 11 Jun 2007
Posts: 649
Followers: 3

Kudos [?]: 28 [0], given: 0

GMAT Tests User
 [#permalink] New post 11 Dec 2007, 08:38
walker wrote:
shubhampandey wrote:
sqrt(X) +ve if x is positive and -ve if x is negative..


√X is always positive.


Very basic question: If √2 = +/- 1.414, why is √X always +ve?
Expert Post
CEO
CEO
User avatar
Joined: 17 Nov 2007
Posts: 3600
Concentration: Entrepreneurship, Other
Schools: Chicago (Booth) - Class of 2011
GMAT 1: 750 Q50 V40
Followers: 346

Kudos [?]: 1666 [0], given: 354

GMAT ToolKit User GMAT Tests User Premium Member
 [#permalink] New post 11 Dec 2007, 12:03
Expert's post
eyunni wrote:
Very basic question: If √2 = +/- 1.414, why is √X always +ve?


√2 always equal +1.414 not -1.414.
maybe you think about questions like: x²=2, what is x?
in this case we have two solutions: x1=+√2 and x2=-√2, so x=+/-√2
but √2 itself is always positive.
SVP
SVP
User avatar
Joined: 01 May 2006
Posts: 1817
Followers: 8

Kudos [?]: 86 [0], given: 0

GMAT Tests User
 [#permalink] New post 11 Dec 2007, 12:25
walker wrote:
eyunni wrote:
Very basic question: If √2 = +/- 1.414, why is √X always +ve?


√2 always equal +1.414 not -1.414.
maybe you think about questions like: x²=2, what is x?
in this case we have two solutions: x1=+√2 and x2=-√2, so x=+/-√2
but √2 itself is always positive.


I agree with Walker... :)

Also, there is the confusing definition of roots (that is related to x^2 = something).... Any number has 2 roots : sqrt(this number) and -sqrt(this number).
Director
Director
avatar
Joined: 11 Jun 2007
Posts: 649
Followers: 3

Kudos [?]: 28 [0], given: 0

GMAT Tests User
 [#permalink] New post 11 Dec 2007, 12:57
Thanks Fig. OA is C. Also, drawing the graphs for (1) and (2) proves that x > y.
  [#permalink] 11 Dec 2007, 12:57
    Similar topics Author Replies Last post
Similar
Topics:
2 Experts publish their posts in the topic Is x>3 ? 1. (x-1)(x-2)(x-3)>0 2. x>1 parama79 12 16 Oct 2011, 16:14
DS is X>Y ? poohv005 1 01 May 2010, 06:25
(D/S) |2X| = |3Y|, is X >Y? pretttyune 5 10 Dec 2007, 05:08
DS - X > Y^2? leeye84 4 04 Aug 2007, 11:13
DS: Is X+Y>0 ??? humtum0 3 04 Jul 2007, 19:38
Display posts from previous: Sort by

ds: Is 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®.