Find all School-related info fast with the new School-Specific MBA Forum

 It is currently 04 Jul 2015, 00:41

GMAT Club Daily Prep

Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

Is XYZ > 0? 1) XY > 0 2) YZ> 0

Author Message
TAGS:
Director
Joined: 17 Oct 2005
Posts: 938
Followers: 1

Kudos [?]: 68 [0], given: 0

Is XYZ > 0? 1) XY > 0 2) YZ> 0 [#permalink]  07 Jan 2006, 15:13
00:00

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 0 sessions
Is XYZ > 0?

1) XY > 0

2) YZ> 0
Intern
Joined: 13 Nov 2005
Posts: 29
Followers: 0

Kudos [?]: 0 [0], given: 0

I'd say E - both (1) and (2) are not sufficient to conclude that xyz > 0 because:

For xyz > 0, either x,y,z > 0 or any two are < 0 and the third > 0

(1) says xy > 0 but says nothing about z - so its not sufficient by itself
(2) says yz > 0 but again says nothing about x - so its not sufficient by itself

Therefore, answer is either C or E.

If xy > 0 either x and y are both > 0 or x and y are both < 0.

Case 1:
x and y are both > 0
Then z is also > 0 (since yz > 0 from (2))
And xyz will be > 0

Case 2:
x and y are both < 0
Then z must be < 0 (since yz > 0 from (2)
And xyz will be < 0

Hence (1) and (2) together are not sufficient.

_________________

Help me crack the GMAT .. !!

GMAT Club Legend
Joined: 07 Jul 2004
Posts: 5068
Location: Singapore
Followers: 23

Kudos [?]: 194 [0], given: 0

(1) Insufficient. Z could be negative.
(2) Insufficient. X could be negative.

Using (1) and (2), insufficient, X,Y and Z could all be negative or positive.

Ans E
Director
Joined: 04 Oct 2005
Posts: 586
Location: Chicago
Followers: 1

Kudos [?]: 5 [0], given: 0

E for me too

A) Insifficeint
B)Insufficient

Both : becomes negative if all 3 are negative and positive if all 3 postive..so Insifficient
Similar topics Replies Last post
Similar
Topics:
8 If xyz > 0, is x > 0? (1) xy > 0 (2) xz > 0 9 10 Jan 2010, 18:31
If xyz > 0, is x > 0? (1) xy > 0 (2) xz > 0 5 31 Mar 2008, 11:43
Source: GMATPrep If xyz>0, is x > 0? (1) xy>0 (2) 2 21 Sep 2007, 20:43
If x>y>z, is xz>0? 1) xy<0 2) yz>0 5 19 Mar 2006, 06:02
If xyz > 0, is x > 0? (1) xy > 0 (2) xz > 0 7 17 Dec 2005, 22:49
Display posts from previous: Sort by