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

It is currently 22 Aug 2014, 09:46

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

if x>y>0, which of the following must be true? I.

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
Manager
Manager
User avatar
Joined: 25 Jul 2006
Posts: 97
Followers: 1

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

GMAT Tests User
if x>y>0, which of the following must be true? I. [#permalink] New post 29 May 2007, 16:00
if x>y>0, which of the following must be true?

I. root(x) - root(y) < root(x-y)
II. x^2 - y^2 > (x-y)^2

1. None
2. I only
3. II only
4. I and II
5. Cannot be determined

If you can, please provide an ALGEBRAIC SOLUTION/DERIVATION/PROOF for the two inequations. I got some answers after testing with several numbers - but it took a while and number plug-in method makes me unsure. Thanks.
Manager
Manager
avatar
Joined: 04 May 2007
Posts: 111
Followers: 1

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

 [#permalink] New post 29 May 2007, 19:18
i don't know of an algebraic/proof way to answer this q- there are some smart people on this board who might have a 'number theory' type of answer/explanation for you... but sometimes i think you just gotta plug in.

i think you can answer this quickly by picking an x and y value that satisfies the inequality (x is bigger than y, y is bigger than zero) and keeping the x and y the same acorss inequalities keeps it consistent

i pikced 100 and 36

10-6<8>16 yup

you can estimate with fractions even:

x=1/4 y=1/9

I: 1/2-1/3 < square root 5/36
1/6 < use 4/36 instead (a smaller # but easy to find root of)

1/6<2/6 yup!
Manager
Manager
avatar
Joined: 28 Aug 2006
Posts: 160
Followers: 2

Kudos [?]: 12 [0], given: 0

GMAT Tests User
 [#permalink] New post 29 May 2007, 19:38
Its 4. Both Statements I and II are true.

Since X and Y are positive. We will have to check when X and Y are integers and when they are between 0 and 1 (0<x>1 and 0<Y>1).

When you simplify stat II we get
2XY>y^2, Plug in values below

I used X=4 and Y=9 for integers and X=1/4 and Y=1/9 and found that both statements are valid.
  [#permalink] 29 May 2007, 19:38
    Similar topics Author Replies Last post
Similar
Topics:
1 Experts publish their posts in the topic If x>0, which of the following must be true? goodyear2013 1 13 Aug 2014, 09:18
x<y and z>0 which of the following must be true? Capthan 2 20 Mar 2008, 06:11
If I x I > 1, which of the following must be true? cpcalanoc 2 19 Dec 2004, 17:35
5 numbers mprts>0, which of the following must be true? karovd 1 24 Nov 2004, 07:30
5 numbers mprts>0, which of the following must be true? karovd 2 24 Nov 2004, 07:29
Display posts from previous: Sort by

if x>y>0, which of the following must be true? I.

  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®.