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

Redeem

gmatprep question

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Junior | Next Rank: 30 Posts
Posts: 25
Joined: Sat Mar 27, 2010 9:00 am

gmatprep question

by JGaynor » Fri Apr 09, 2010 4:20 pm
This is a pretty simple question, but I don't know why I can't get the correct answer....

If x-y>10, is x-y>x+y?

1) x=8
2) y=-20

Any insight will be appreciated- I checked the forums and couldnt find this posted...

OA:[spoiler]D; I can prove statement 1 sufficient, but for statement 2 I come out with a possibility that x-y is equal to 10..??[/spoiler]

Jason
Top
Source: — Data Sufficiency |
User avatar
Legendary Member
Posts: 1560
Joined: Tue Nov 17, 2009 2:38 am
Thanked: 137 times
Followed by:5 members

by thephoenix » Fri Apr 09, 2010 6:50 pm
for s2)
x-y>10 and y=-20----->x+20>10----->x>-10{so x is -9.9.......to ......infinity}
now in that case x+y=x-20 ; lets try with some value of x say x=-9.9 then x-y=-9.9+20=10.1 and x+y=-9.9-20=-29.9
clearly x-y>x+y.
now for x=1000 x-y=1000+20=1020 and x+y=1000-20=980 clearly x-y>x+y
hence for any value of x >-10 we get x-y>x+y
suff
Top
User avatar
Community Manager
Posts: 1537
Joined: Mon Aug 10, 2009 6:10 pm
Thanked: 653 times
Followed by:252 members

by papgust » Fri Apr 09, 2010 7:16 pm
x-y > 10.....(1)

Is x-y > x+y? OR Is y < 0?

1. x=8

Sub x in (1),
8-y > 10
y < -2. y is definitely less than 0.

Sufficient.

2. y=-8

Answers the question is y<0 ?
YES

Sufficient
Top
Junior | Next Rank: 30 Posts
Posts: 25
Joined: Sat Mar 27, 2010 9:00 am

by JGaynor » Fri Apr 09, 2010 7:32 pm
ahhh I see...thank you very much!
Top
Newbie | Next Rank: 10 Posts
Posts: 9
Joined: Wed Mar 24, 2010 4:51 am
Thanked: 1 times

by meghash3 » Sat Apr 10, 2010 6:29 am
when options give values, substitution seems to be the best bet.
Top
Post new topic Post Reply
• Page 1 of 1