slope of line X is m, and slope of line Y is n. Is line X : DS Archive
Check GMAT Club App Tracker for the Latest School Decision Releases http://gmatclub.com/AppTrack

It is currently 02 Dec 2016, 16:22
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.

Close

Request Expert Reply

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

slope of line X is m, and slope of line Y is n. Is line X

  post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
Director
Director
avatar
Joined: 14 Sep 2005
Posts: 993
Location: South Korea
Followers: 2

Kudos [?]: 153 [0], given: 0

slope of line X is m, and slope of line Y is n. Is line X [#permalink]

Show Tags

New post 28 Oct 2005, 05:38
00:00
A
B
C
D
E

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.

slope of line X is m, and slope of line Y is n. Is line X parellel to line Y ?

1) m+n = -1
2) m*n = 1/4
_________________

Auge um Auge, Zahn um Zahn :twisted: !

SVP
SVP
User avatar
Joined: 24 Sep 2005
Posts: 1890
Followers: 19

Kudos [?]: 287 [0], given: 0

Re: DS - line [#permalink]

Show Tags

New post 28 Oct 2005, 05:43
gamjatang wrote:
slope of line X is m, and slope of line Y is n. Is line X parellel to line Y ?

1) m+n = -1
2) m*n = 1/4


X//Y <===> m=n
1) doesn't lead to m=n-->insuff
2) doesn't lead to m=n--->insuff

1 and 2.
m=-1-n
---> m*n= -n-n^2=1/4----> n^2+n+1/4=0 ----> (n+1/2)^2=0 ---->
n=-1/2 ----> m=-1-(-1/2)= -1/2
So m=n=-1/2 ---> X//Y ----> suff

Last edited by laxieqv on 28 Oct 2005, 06:39, edited 1 time in total.
Manager
Manager
avatar
Joined: 17 Sep 2005
Posts: 72
Location: California
Followers: 1

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

 [#permalink]

Show Tags

New post 28 Oct 2005, 12:44
It's C.

Q: Is X parallel to Y ?
When lines are parallel their slopes are equal.
So is m=n?

1) m+n = -1
Infinite possibilities for m,n:
-1/2, -1/2
0, -1
-1, 0
...
NOT SUFF => BCE

2) m*n = 1/4
Again infinite possibilities for m,n:
-1/2, -1/2
1, 1/4
1/4, 1
...
NOT SUFF => CE

1+2) taken together we have 2 equations and two unknowns
Solving we get (m + 1/2)^2=0 which means one unique val for m = -1/2
therefore -1/2*n=1/4 => n = -1/2 or m=n
SUFF => C
Director
Director
avatar
Joined: 14 Sep 2005
Posts: 993
Location: South Korea
Followers: 2

Kudos [?]: 153 [0], given: 0

 [#permalink]

Show Tags

New post 30 Oct 2005, 05:36
Thanks for the discussion.

The answer is E.

There's a possibility that the two lines are actually one same line, and none of the subconditions (1, 2, 1+2) clarify this.
_________________

Auge um Auge, Zahn um Zahn :twisted: !

SVP
SVP
User avatar
Joined: 24 Sep 2005
Posts: 1890
Followers: 19

Kudos [?]: 287 [0], given: 0

 [#permalink]

Show Tags

New post 30 Oct 2005, 05:49
gamjatang wrote:
Thanks for the discussion.

The answer is E.

There's a possibility that the two lines are actually one same line, and none of the subconditions (1, 2, 1+2) clarify this.


good trap! 8-)
  [#permalink] 30 Oct 2005, 05:49
Display posts from previous: Sort by

slope of line X is m, and slope of line Y is n. Is line X

  post reply Question banks Downloads My Bookmarks Reviews Important topics  


GMAT Club MBA Forum Home| About| 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®.