If y does not equal 0. Does x = 0 ? : GMAT Data Sufficiency (DS)
Check GMAT Club Decision Tracker for the Latest School Decision Releases http://gmatclub.com/AppTrack

 It is currently 17 Jan 2017, 04:07

### 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

# If y does not equal 0. Does x = 0 ?

Author Message
TAGS:

### Hide Tags

Director
Joined: 07 Jun 2004
Posts: 612
Location: PA
Followers: 5

Kudos [?]: 705 [1] , given: 22

If y does not equal 0. Does x = 0 ? [#permalink]

### Show Tags

06 Jan 2011, 05:32
1
KUDOS
5
This post was
BOOKMARKED
00:00

Difficulty:

55% (hard)

Question Stats:

52% (02:28) correct 48% (00:55) wrong based on 191 sessions

### HideShow timer Statistics

If y does not equal 0. Does x = 0 ?

(1) x^2*y = x^3*y
(2) x^2/y = x^3*y
[Reveal] Spoiler: OA

Last edited by Bunuel on 07 Oct 2014, 06:55, edited 2 times in total.
Math Expert
Joined: 02 Sep 2009
Posts: 36530
Followers: 7070

Kudos [?]: 92960 [3] , given: 10541

Re: If y does not equal 0. Does x = 0 ? [#permalink]

### Show Tags

06 Jan 2011, 05:45
3
KUDOS
Expert's post
2
This post was
BOOKMARKED
rxs0005 wrote:
If y <> = 0 Does x = 0

x^2 y = x^3 y

x^2 / y = x^3 y

Given: $$y\neq{0}$$. Question does $$x=0$$?

(1) x^2*y=x^3*y --> as $$y\neq{0}$$ we can reduce by $$y$$ --> $$x^2=x^3$$ --> $$x^2(x-1)=0$$ --> either $$x=0$$ or $$x=1$$. Not sufficient.

(2) x^2/y=x^3*y --> $$x^2=x^3y^2$$ --> $$x^2(xy^2-1)=0$$ --> either $$x=0$$ or $$xy^2=1$$ (depending on $$y$$ $$x$$ can be any positive number). Not sufficient.

(1)+(2) Both $$x=0$$ and $$x=1$$ (in this case $$y=1$$ or $$y=-1$$) satisfy the statements. Not sufficient.

_________________
Manager
Joined: 20 Jul 2011
Posts: 152
GMAT Date: 10-21-2011
Followers: 3

Kudos [?]: 68 [0], given: 15

Re: If y does not equal 0. Does x = 0 ? [#permalink]

### Show Tags

07 Sep 2011, 04:19
**
Quote:
If y <> = 0 Does x = 0

(1) x^2 y = x^3 y

(2) x^2 / y = x^3 y

Very clear explanation, Bunuel. Thanks!
Initially, I had answer A and realised my mistake after reading Bunuel's solution. My error came from the fact that I cross-multiplied and eliminated as below:
Quote:
From Statement 1
--> x^2y=x^3y --> y/y = x^3/x^2 --> x = 1
Sufficient

Given y does not equal to zero, does x=0?

Statement 1
x^2y = x^3y --> x^3=x^2 --> 0 = x^2(x-1)
So, x=0 or x=1
Insufficient.

Statement 2
x^2/y = x^3y --> 0 = x^2(xy^2-1)
So, x=0 or xy^2=1 (i.e. x is not zero)
Insufficient.

Statement 1 + 2
x^2(x-1) = x^2(xy^2-1)
x-1 = xy^2-1
x(1-y^2) = 0
So, x = 0 or x does not equals to zero (when y^2=1)
Insufficient.

_________________

"The best day of your life is the one on which you decide your life is your own. No apologies or excuses. No one to lean on, rely on, or blame. The gift is yours - it is an amazing journey - and you alone are responsible for the quality of it. This is the day your life really begins." - Bob Moawab

Director
Status: Final Countdown
Joined: 17 Mar 2010
Posts: 563
Location: India
GPA: 3.82
WE: Account Management (Retail Banking)
Followers: 17

Kudos [?]: 278 [0], given: 75

Re: If y does not equal 0. Does x = 0 ? [#permalink]

### Show Tags

26 Aug 2012, 09:55
Very nice explanation Bunuel , thanks a lot !

I was confused whether to choose D or E because i thought that in either of the options x is coming 0 (along with some other value)

But it suggests that the value is not sufficient in both the cases.
_________________

" Make more efforts "
Press Kudos if you liked my post

Senior Manager
Joined: 02 Sep 2012
Posts: 259
Location: United States
Concentration: Entrepreneurship, Finance
GMAT Date: 07-25-2013
GPA: 3.83
WE: Architecture (Computer Hardware)
Followers: 5

Kudos [?]: 179 [0], given: 99

Re: If y does not equal 0. Does x = 0 ? [#permalink]

### Show Tags

29 Dec 2012, 01:21
If y does not equal 0. Does x = 0 ?

(1) x^2 y = x^3 y
(2) x^2 / y = x^3 y

please do calrify my doubt :

Given:
y does not equal to zero, does x=0?

x^2y = x^3y

Here we are calculating as x^2y-x^3y
my question is
why can't we do as x^2y/x^3y

Please do clarify when what is the actual procedure and why can't do like this as mentioned later
_________________

"Giving kudos" is a decent way to say "Thanks" and motivate contributors. Please use them, it won't cost you anything

Math Expert
Joined: 02 Sep 2009
Posts: 36530
Followers: 7070

Kudos [?]: 92960 [0], given: 10541

Re: If y does not equal 0. Does x = 0 ? [#permalink]

### Show Tags

29 Dec 2012, 02:51
skamal7 wrote:
If y does not equal 0. Does x = 0 ?

(1) x^2 y = x^3 y
(2) x^2 / y = x^3 y

please do calrify my doubt :

Given:
y does not equal to zero, does x=0?

x^2y = x^3y

Here we are calculating as x^2y-x^3y
my question is
why can't we do as x^2y/x^3y

Please do clarify when what is the actual procedure and why can't do like this as mentioned later

Merging similar topics. Please refer to the solutions above.

Next, I guess your question is why are not we dividing both parts of x^2*y = x^3*y by x^3*y to get x^2*y/(x^3*y) = 1. That's because x^3*y can be zero (in case y=0) and we cannot divide by 0.

Hope it's clear.
_________________
GMAT Club Legend
Joined: 09 Sep 2013
Posts: 13423
Followers: 575

Kudos [?]: 163 [0], given: 0

Re: If y does not equal 0. Does x = 0 ? [#permalink]

### Show Tags

13 Nov 2014, 13:43
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: If y does not equal 0. Does x = 0 ?   [#permalink] 13 Nov 2014, 13:43
Similar topics Replies Last post
Similar
Topics:
6 If wxyz does not equal 0, is w/x > y/z? 5 08 Sep 2015, 23:36
2 Does x + y = 0? 4 11 Dec 2014, 06:05
11 If x and y are integers and xy does not equal 0, is xy < 0? 6 15 Oct 2014, 15:49
6 If wxy ≠ 0, does x = y ? 5 07 Dec 2013, 23:08
5 If x and y are integers and xy does not equal 0, is xy < 17 09 Aug 2009, 04:02
Display posts from previous: Sort by