If r and s are positive integers, is (r/s) an integer? : DS Archive
Check GMAT Club Decision Tracker for the Latest School Decision Releases http://gmatclub.com/AppTrack

 It is currently 24 Jan 2017, 09:28

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 r and s are positive integers, is (r/s) an integer?

 post reply Question banks Downloads My Bookmarks Reviews Important topics
Author Message
Senior Manager
Joined: 10 Mar 2008
Posts: 371
Followers: 5

Kudos [?]: 259 [0], given: 0

If r and s are positive integers, is (r/s) an integer? [#permalink]

Show Tags

22 Sep 2008, 11:03
1
This post was
BOOKMARKED
00:00

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 0 sessions

HideShow timer Statistics

This topic is locked. If you want to discuss this question please re-post it in the respective forum.

Is xy > x^2y^2?
(1) 14x^2 = 3
(2) y^2 = 1

SVP
Joined: 17 Jun 2008
Posts: 1569
Followers: 11

Kudos [?]: 250 [0], given: 0

Show Tags

22 Sep 2008, 11:54
what the question is asking is whether 0<xy<1

From stmt1: x^2 = 3/14, hence x = sqrt(3/14), -sqrt(3/14).

From stmt2: y = 1, -1

Combining stmt1 and 2, xy = sqrt(3/14), -sqrt(3/14). Hence, not sufficient.

Hence, E.
Senior Manager
Joined: 10 Mar 2008
Posts: 371
Followers: 5

Kudos [?]: 259 [0], given: 0

Show Tags

23 Sep 2008, 09:39
I was able to successfully solve this problem by plugging numbers. But, I'm looking to learn faster ways of solving such problems.

Could you please explain as to how you came to the conclusion that the question is essentially asking: 0<xy<1. Thanks
Intern
Joined: 17 Sep 2008
Posts: 6
Schools: Chicago Booth, Wharton, MIT, Haas
Followers: 0

Kudos [?]: 8 [0], given: 0

Show Tags

23 Sep 2008, 15:06
The inequality reduces to :
x^2y^2 - xy < 0
or xy(xy-1) < 0

This implies 0<xy<1
But instead of trying to derive this for the GMAT, you should probably remember that x^2<x implies 0<x<1
SVP
Joined: 29 Aug 2007
Posts: 2492
Followers: 68

Kudos [?]: 737 [0], given: 19

Show Tags

23 Sep 2008, 17:20
icandy wrote:
Please underline SC questions.

Please Do not post OA along with the Q.

Give and take Kudos.

in addition to that, most importattly, mention the source of the question.
_________________

Gmat: http://gmatclub.com/forum/everything-you-need-to-prepare-for-the-gmat-revised-77983.html

GT

VP
Joined: 05 Jul 2008
Posts: 1430
Followers: 39

Kudos [?]: 360 [0], given: 1

Show Tags

23 Sep 2008, 18:48
GMAT TIGER wrote:
icandy wrote:
Please underline SC questions.

Please Do not post OA along with the Q.

Give and take Kudos.

in addition to that, most importattly, mention the source of the question.

If you were just making a point, thats fine. if you were thinking that I posted the Q, that was not me. I was annoyed with people posting OA along with Q and not underlining the SC Q. Thats how it came out.
SVP
Joined: 29 Aug 2007
Posts: 2492
Followers: 68

Kudos [?]: 737 [0], given: 19

Show Tags

23 Sep 2008, 21:19
icandy wrote:
GMAT TIGER wrote:
icandy wrote:
Please underline SC questions.

Please Do not post OA along with the Q.

Give and take Kudos.

in addition to that, most importattly, mention the source of the question.

If you were just making a point, thats fine. if you were thinking that I posted the Q, that was not me. I was annoyed with people posting OA along with Q and not underlining the SC Q. Thats how it came out.

all your signature lines make sense. if you add "Always mention the source of the question" in your signature line, your signature lines would be a summary of gmat club forum etiquette.
_________________

Gmat: http://gmatclub.com/forum/everything-you-need-to-prepare-for-the-gmat-revised-77983.html

GT

Senior Manager
Joined: 04 Sep 2008
Posts: 259
Location: Kolkata
Schools: La Martiniere for Boys
Followers: 2

Kudos [?]: 90 [0], given: 9

Show Tags

26 Sep 2008, 11:03
If we combine the 2 statements we have to prove that xy > 3/14.

Possible values of x are +/- (3/14)^1/2 and that of y are +/- 1

For all combinations of xy we get xy < 3/14

The ans is therefore C

Please correct me if I am wrong
Re: DS   [#permalink] 26 Sep 2008, 11:03
Display posts from previous: Sort by

If r and s are positive integers, is (r/s) an integer?

 post reply Question banks Downloads My Bookmarks Reviews Important topics

 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®.