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

It is currently 02 Aug 2015, 03:29
GMAT Club Tests

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

are x and y both positive?

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
Intern
Intern
avatar
Joined: 21 Jan 2007
Posts: 11
Followers: 0

Kudos [?]: 3 [0], given: 0

are x and y both positive? [#permalink] New post 09 Jul 2007, 10:24
00:00
A
B
C
D
E

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 1 sessions
This topic is locked. If you want to discuss this question please re-post it in the respective forum.

are x and y both positive?

a. 2x-2y = 1
b. x/y > 1

please explain your answer as well...
Senior Manager
Senior Manager
avatar
Joined: 04 Jun 2007
Posts: 346
Followers: 1

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

Re: gmatprep - DS question [#permalink] New post 09 Jul 2007, 10:48
dmittal wrote:
are x and y both positive?

a. 2x-2y = 1
b. x/y > 1

please explain your answer as well...


From stmt 1: 2*(x-y) = 1 => x-y = 1/2; x>y. x,y could be either +ve or -ve. Insufficient.

From stmt 2: x/y > 1 => |x| > |y| and x,y both have same sign (+ve or -ve). Insufficient.

From both stmts: Cannot tell if +ve or -ve. Insufficient. Hence, E.
Intern
Intern
avatar
Joined: 21 Jan 2007
Posts: 11
Followers: 0

Kudos [?]: 3 [0], given: 0

 [#permalink] New post 09 Jul 2007, 11:21
if x > y and either both x, and are +ve or -ve
then
based on equation x = 1/2 + y => both x and y are +ve. Right?
Intern
Intern
avatar
Joined: 19 Jan 2007
Posts: 3
Followers: 0

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

 [#permalink] New post 09 Jul 2007, 14:46
dmittal wrote:
if x > y and either both x, and are +ve or -ve
then
based on equation x = 1/2 + y => both x and y are +ve. Right?


Hi all, I'm new here but figured I'd jump right in!!

I agree with you on this one. Taking the two statements together we know abs(x) must be greater than abs(y) and that x and y are either both positive or both negative.

We also know that 2x - 2y = 1.

2(x-y) = 1
x - y = 1/2
x = 1/2 + y

There is no way abs(x) could be greater than abs(y) if x and y were both negative.

x = -2

-2 = 1/2 + y
-5/2 = y

abs(-2) < abs(-5/2)

x = -4
-4 = 1/2 + y
-9/2 = y

abs (-4) < abs(-9/2)

I'm going with C for my answer.





T
Senior Manager
Senior Manager
User avatar
Joined: 24 Nov 2006
Posts: 351
Followers: 1

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

Re: gmatprep - DS question [#permalink] New post 09 Jul 2007, 18:30
dmittal wrote:
are x and y both positive?

a. 2x-2y = 1
b. x/y > 1



(1) x - y = 1/2. Insuf.

(2) Insuf.

(1&2) From (2), x and y are both +ve or both -ve. There are infinite combinations of x and y so that (1) holds. What we must demonstrate is that there´s no combination of x, y -ve so that (1) holds.

Let x, y be both -ve and x/y >1, then x<y. Therefore, x-y<0, cannot be = 1/2 in any circumstance, then (1&2) are sufficient to state that both x and y are -ve, and the answer is C.
GMAT Club Legend
GMAT Club Legend
User avatar
Joined: 07 Jul 2004
Posts: 5067
Location: Singapore
Followers: 24

Kudos [?]: 201 [0], given: 0

 [#permalink] New post 09 Jul 2007, 19:05
st1:
x-y = 1/2. Can be x = -1/4, y = -3/4, or x = 1, y = 1/2. Insufficient.

st2:
x and y must be both positive or both negative. Insufficient.

using both, we still can't tell which set is applicable.

Ans E
  [#permalink] 09 Jul 2007, 19:05
Display posts from previous: Sort by

are x and y both positive?

  Question banks Downloads My Bookmarks Reviews Important topics  


cron

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®.