• 7 CATs FREE!
    If you earn 100 Forum Points

    Engage in the Beat The GMAT forums to earn
    100 points for $49 worth of Veritas practice GMATs FREE

    Veritas Prep
    VERITAS PRACTICE GMAT EXAMS
    Earn 10 Points Per Post
    Earn 10 Points Per Thanks
    Earn 10 Points Per Upvote
    REDEEM NOW
This topic has expert replies
Master | Next Rank: 500 Posts
Posts: 301
Joined: 22 Apr 2008
Thanked: 2 times

inequalities

by beater » Fri Sep 05, 2008 11:47 am
If x + y + z > 0, is z > 1?

1. z > x + y + 1
2. x + y + 1 < 0

Please explain!

Legendary Member
Posts: 683
Joined: 22 Jul 2008
Location: Dubai
Thanked: 73 times
Followed by:2 members

by mals24 » Fri Sep 05, 2008 12:34 pm
Given: x+y+z>0----equ 1

St 1: z>x+y+1

adding the two equations you get: x+y+2z>x+y+1
canceling x+y from both sides you get: 2z>1--->z>0.5-----INSUFF

St 2: x+y+1<0-----equ 2
we need to change the less than sign to greater than in order to add it with equ 1
Hence multiply -1 in equ 2 which gives us---> -(x+y+1)>0
Now add this equ with equ 1 and we get ----> z-1>0
ie z>1 SUFF

Hence B is the answer