Absolute value

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

jfranco23: Senior | Next Rank: 100 Posts; Posts: 75; Joined: Fri Jan 16, 2009 2:00 pm; Thanked: 1 times; GMAT Score:550

Absolute value

by jfranco23 » Tue Feb 17, 2009 4:02 pm

If xy + z = z, is /x-y/>0?

1. x not equal 0
2. y = 0

Quote

Source: Beat The GMAT — Data Sufficiency | Tue Feb 17, 2009 4:02 pm

earth@work: Master | Next Rank: 500 Posts; Posts: 248; Joined: Mon Aug 11, 2008 9:51 am; Thanked: 13 times

by earth@work » Tue Feb 17, 2009 4:38 pm

is the OA- A

xy + z = z means xy=0 i.e either x=0 or y=0 or both equal to 0

1. x not equal 0 this implies y=0 ==> lx-0l>0 for all x not equal to zero ... sufficient

2. y=0; means either x=0 or x not equal to 0
case 1..if x=0 then lx-yl is not greater than 0
case 2...if x not equal to 0 then lx-yl >0 ..... two contradictory answers...so 2 is insufficient
ans:A

Quote

x2suresh: Master | Next Rank: 500 Posts; Posts: 258; Joined: Thu Aug 07, 2008 5:32 am; Thanked: 16 times

by x2suresh » Tue Feb 17, 2009 10:30 pm

earth@work wrote:is the OA- A

xy + z = z means xy=0 i.e either x=0 or y=0 or both equal to 0

1. x not equal 0 this implies y=0 ==> lx-0l>0 for all x not equal to zero ... sufficient

2. y=0; means either x=0 or x not equal to 0
case 1..if x=0 then lx-yl is not greater than 0
case 2...if x not equal to 0 then lx-yl >0 ..... two contradictory answers...so 2 is insufficient
ans:A

agree with your logic