GMAT Question of the Day - Daily to your Mailbox; hard ones only

 It is currently 18 Aug 2018, 11:36

### 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

# Is x(y/z) > 0?

Author Message
TAGS:

### Hide Tags

Senior Manager
Joined: 24 Jun 2012
Posts: 346
Location: Pakistan
GPA: 3.76

### Show Tags

Updated on: 26 Dec 2013, 03:53
1
1
00:00

Difficulty:

25% (medium)

Question Stats:

79% (00:59) correct 21% (00:59) wrong based on 203 sessions

### HideShow timer Statistics

Is x(y/z) > 0?

(1) xyz > 0
(2) yz > 0

_________________

Push yourself again and again. Don't give an inch until the final buzzer sounds. -Larry Bird
Success isn't something that just happens - success is learned, success is practiced and then it is shared. -Sparky Anderson
-S

Originally posted by sananoor on 29 Dec 2012, 08:51.
Last edited by Bunuel on 26 Dec 2013, 03:53, edited 1 time in total.
Edited the OA.
Board of Directors
Joined: 01 Sep 2010
Posts: 3445
Re: Is x(y/z) > 0?  [#permalink]

### Show Tags

29 Dec 2012, 10:52
sananoor wrote:
Is x(y/z) > 0?

(1) xyz > 0
(2) yz > 0

Statement$$\frac{xy}{z}$$ $$>0$$ both are positive or negative (the numerator and the denominator)

1) $$xyz$$ $$> 0$$ this says that our variables are both positive or negative but we can't determine which of them are positive or negative

2) the product of $$y*z$$ are both positive or negative

1) + 2) we still do not know which of our variable are positive or negative

E is the best
_________________
Senior Manager
Joined: 24 Jun 2012
Posts: 346
Location: Pakistan
GPA: 3.76
Re: Is x(y/z) > 0?  [#permalink]

### Show Tags

29 Dec 2012, 11:17
statement 1) says xyz> 0 from this we conclude that either all three are positive or two are negative. statement 2 says that yz> 0 it means either both are negative or positive....by combining two statements we come to know that x is positive...x cant be negative in order to make the statement one right....xyz>0 and yz> 0....so x is positive...y and z are either positive or negative....x(y/z) >0 if y and z are negative then negative signs cancel each other and answer could be greater than 0...i am so much confused regarding this question...
_________________

Push yourself again and again. Don't give an inch until the final buzzer sounds. -Larry Bird
Success isn't something that just happens - success is learned, success is practiced and then it is shared. -Sparky Anderson
-S

Intern
Joined: 18 Dec 2011
Posts: 2
Re: Is x(y/z) > 0?  [#permalink]

### Show Tags

30 Dec 2012, 02:23
1
guys, dont think E is the correct answer... As per me , its A

here is the explanation:

1) it says xyz>0 which means either two of these variables are negative or all three are positive...you can take out any combinations from these and you will find out that every combination gives you x (y/z) >0.. so, this seems sufficient

2) yz>0 doesn't give any information about x so insufficient
Manager
Joined: 31 May 2012
Posts: 145
Re: Is x(y/z) > 0?  [#permalink]

### Show Tags

30 Dec 2012, 05:13
Is x(y/z) > 0?

(1) xyz > 0
(2) yz > 0

We need to know whether expression E= {x * y * (1/y)} positive or negative.
Let E = A*B*C where { A=x, B=y, C=1/y }
Expression will be -ve if, 1 OR 3 terms among A,B & C are –ve. That is..
1. Any 1 term out of of A,B and C is –ve and 2 are +ve. OR
2. All 3 A, B & C are –ve.

Option 1: xyz>0..
Again we can write this as ABC>0.. So, this option is sufficient. Multiplication and Division provide similar signs.

Option 2: yz>0.
This means, Both y & z are –ve Or Both are +ve. We can’t determine whether x(y/z)>0.

Intern
Joined: 21 Mar 2009
Posts: 19
Re: Is x(y/z) > 0?  [#permalink]

### Show Tags

31 Dec 2012, 07:13
sananoor wrote:
Is x(y/z) > 0?

(1) xyz > 0
(2) yz > 0

Multiplication or division doesn't change the sign of a term. So x(y/z) or xyz or any formation of xyz will be same as long as one of that is established.

In option 1. xyz>0 is sufficient to determine thus that x(y/z) > 0. Suff

Option 2, nithing is known about x so not suff.

Ans A
SVP
Joined: 06 Sep 2013
Posts: 1851
Concentration: Finance
Re: Is x(y/z) > 0?  [#permalink]

### Show Tags

25 Dec 2013, 17:17
sananoor wrote:
Is x(y/z) > 0?

(1) xyz > 0
(2) yz > 0

So is it A or E finally?

Cheers!
J
Math Expert
Joined: 02 Sep 2009
Posts: 47983
Re: Is x(y/z) > 0?  [#permalink]

### Show Tags

26 Dec 2013, 03:58
jlgdr wrote:
sananoor wrote:
Is x(y/z) > 0?

(1) xyz > 0
(2) yz > 0

So is it A or E finally?

Cheers!
J

Correct answer is A. Edited the OA. Thank you.

Is x(y/z) > 0?

We need to find whether x*y*1/z is positive.

(1) xyz > 0. Since z and 1/z have the same sign, then this statement implies that x*y*1/z > 0. Sufficient.

(2) yz > 0. If x > 0, then x*y*1/z is positive but if x <= 0, then x*y*1/z is not positive. Not sufficient.

Hope it's clear.
_________________
Non-Human User
Joined: 09 Sep 2013
Posts: 7759
Re: Is x(y/z) > 0?  [#permalink]

### Show Tags

20 Mar 2018, 17:57
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________
Re: Is x(y/z) > 0? &nbs [#permalink] 20 Mar 2018, 17:57
Display posts from previous: Sort by

# Events & Promotions

 Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.