BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

In the xy-coordinate plane, line l and line k intersect

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
User avatar
Master | Next Rank: 500 Posts
Posts: 298
Joined: Sun Jun 03, 2012 6:42 am
Location: New delhi
Thanked: 10 times
Followed by:7 members
GMAT Score:590

In the xy-coordinate plane, line l and line k intersect

by varun289 » Thu Dec 13, 2012 11:39 am
210. In the xy-coordinate plane, line l and line k intersect at the point (4, 3). Is the product of their slopes negative?
(1) The product of the x-intercepts of lines l and k is positive.
(2) The product of the y-intercepts of lines l and k is negative.
Top
Source: — Problem Solving |
Master | Next Rank: 500 Posts
Posts: 131
Joined: Wed Nov 14, 2012 2:01 pm
Thanked: 39 times
Followed by:2 members

by puneetkhurana2000 » Thu Dec 13, 2012 12:03 pm
K=a1x+b1
L=a2x+b2
Is a1a2 < 0 ?

Statement 1)

(-b1/a1) x (- b2/a2) > 0 or b1b2/a1a2 > 0

We don't know if both are either positive or negative, so Not Sufficient!!!

Statement 2)

b1b2 < 0

No Information about a1a2, so Not Sufficient!!!

Together

b1b2/a1a2 > 0
b1b2 < 0

Hence, a1a2 < 0

Answer C

Note: - The information that they intersect at (4,3) is irrelevant unless you solve this by drawing some lines. If algebra to be used, we don't need this information as explained above.

Hope this helps!!!
Top
Post new topic Post Reply
• Page 1 of 1