Coordinate geometry

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

Redeem

This topic has expert replies

Post new topic Post Reply

Previous Topic Next Topic

pepeprepa: Legendary Member; Posts: 661; Joined: Tue Jul 08, 2008 12:58 pm; Location: France; Thanked: 48 times

Coordinate geometry

by pepeprepa » Sat Aug 23, 2008 3:14 pm

In the xy plane, line k passes through the origin and through the point (a;b) where a different b. Is b positive ?
1) The slope of line k is negative
2) a<b

Quote

Source: Beat The GMAT — Data Sufficiency | Sat Aug 23, 2008 3:14 pm

ebehboud: Senior | Next Rank: 100 Posts; Posts: 31; Joined: Sat Aug 23, 2008 8:23 pm; Location: Toronto; Thanked: 1 times; GMAT Score:610

by ebehboud » Sat Aug 23, 2008 8:31 pm

Okay here is my approach.

Right off the bat we have 4 options
1- positive slope, (a,B) in the second quadrant- b>=0
2- positive slope, (a,B) in the forth quadrant- b<=0
3- negative slope, (a,B) in the first quadrant- b>=0
4- negative slope, (a,B) in the third quadrant, b<=0

(1)Slope<0, we end up with Options 1 and 2.. therefore Insufficient
(2)a<b, could be any of the options 1, 3, and 4.. Insufficient

Together:
The slope has to be negative, then option 1 and 2 are viable,,, and if a<b, then it has to be option 1, a<0 and b>0

C.