Coordinate Geometry question

This topic has expert replies
Source: — Data Sufficiency |

Legendary Member
Posts: 1448
Joined: Tue May 17, 2011 9:55 am
Location: India
Thanked: 375 times
Followed by:53 members

by Frankenstein » Fri Jun 17, 2011 5:23 am
Hi,
(-a,b) and(-b,a) are in the same quadrant. So, a and b must be of the same sign. So, these points can both be in Q2 in a,b > 0
or Q4 if a,b < 0
From(1): xy>0
So, x and y are of same sign.
So,(-x,y) will be in Q2 in x,y > 0
or Q4 if x,y < 0
Not sufficient
From(2): ax>0
So, either both a,x >0 or both a,x <0
No info. about y
Not sufficient

Both (1)&(2):
a,b,x,y should be of the same sign.
Then (-x,y) will be in the same quadrant as (-a,b) (-b,a) are.
Sufficient

Hence, C
Cheers!

Things are not what they appear to be... nor are they otherwise

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 3835
Joined: Fri Apr 02, 2010 10:00 pm
Location: Milpitas, CA
Thanked: 1854 times
Followed by:523 members
GMAT Score:770

by Anurag@Gurome » Fri Jun 17, 2011 5:32 am
Rahul has provided a very elaborate discussion on this one here : https://www.beatthegmat.com/quadrant-pro ... tml#310294
Anurag Mairal, Ph.D., MBA
GMAT Expert, Admissions and Career Guidance
Gurome, Inc.
1-800-566-4043 (USA)

Join Our Facebook Groups
GMAT with Gurome
https://www.facebook.com/groups/272466352793633/
Admissions with Gurome
https://www.facebook.com/groups/461459690536574/
Career Advising with Gurome
https://www.facebook.com/groups/360435787349781/

User avatar
Master | Next Rank: 500 Posts
Posts: 461
Joined: Tue May 10, 2011 9:09 am
Location: pune
Thanked: 36 times
Followed by:3 members

by amit2k9 » Fri Jun 17, 2011 6:41 am
for (x,y) positive quadrant is 2nd
for (x,y) negative quadrant is 4th

x,y cannot be one positive and one negative. hence 3rd and 1st quadrant not considered.

1 x,y both positive then same quadrant.
x,y where x>0 and y<0 quadrant changes. Not sufficient.

2. same as above. not sufficient.


1+2 a,b and x,y are of same signs. thus they will be either in quadrant 2nd or 4th.

sufficient.
hence C.
For Understanding Sustainability,Green Businesses and Social Entrepreneurship visit -https://aamthoughts.blocked/
(Featured Best Green Site Worldwide-https://bloggers.com/green/popular/page2)