Check GMAT Club Decision Tracker for the Latest School Decision Releases https://gmatclub.com/AppTrack

 It is currently 28 May 2017, 16:38

### 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

# Coordinate Geometry

 post reply Question banks Downloads My Bookmarks Reviews Important topics
Author Message
Senior Manager
Joined: 20 Feb 2008
Posts: 295
Location: Bangalore, India
Schools: R1:Cornell, Yale, NYU. R2: Haas, MIT, Ross
Followers: 4

Kudos [?]: 45 [0], given: 0

### Show Tags

04 May 2008, 14:52
This topic is locked. If you want to discuss this question please re-post it in the respective forum.

Could you please provide an explanation for this question, I think I am missing an obvious point here.
Thank you.
Attachments

GMAT Prep 1 Coordinate Geometry.doc [112 KiB]

VP
Joined: 10 Jun 2007
Posts: 1442
Followers: 7

Kudos [?]: 285 [0], given: 0

Re: Coordinate Geometry [#permalink]

### Show Tags

04 May 2008, 15:12
ventivish wrote:
Could you please provide an explanation for this question, I think I am missing an obvious point here.
Thank you.

C for me.

L = m1*x + b1
K = m2 *x + b2

We want to find if m1*m2<0 ?

(1) is given that product of x intercepts is positive
To find x-intercept, set y=0.
For line L: x = -b1/m1
For line K: x = -b2/m2
So we know that
(b1/m1)*(b2/m2) >0
In this case, we don't know b1 or b2, so INSUFFICIENT

(2) is given that product of y intercepts is negative
To find y-intercept, set x=0
For line L: y = b1
For line K: y = b2
So we know that
b1*b2 < 0
Don't know anything about slopes, INSUFFICIENT

Together, we know that
(b1*b2) / (m1*m2) > 0 AND b1*b2 < 0
This means that
m1 * m2 must be negative.
SUFFICIENT
Senior Manager
Joined: 20 Feb 2008
Posts: 295
Location: Bangalore, India
Schools: R1:Cornell, Yale, NYU. R2: Haas, MIT, Ross
Followers: 4

Kudos [?]: 45 [0], given: 0

Re: Coordinate Geometry [#permalink]

### Show Tags

04 May 2008, 17:07
Thank you !!!Makes sense now.
Re: Coordinate Geometry   [#permalink] 04 May 2008, 17:07
Display posts from previous: Sort by

# Coordinate Geometry

 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®.