GMAT Question of the Day: Daily via email | Daily via Instagram New to GMAT Club? Watch this Video

It is currently 06 Aug 2020, 02:50

Close

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
Your Progress

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

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

Close

Request Expert Reply

Confirm Cancel

If xy ≠ 0, what is the value of (x^4*y^2- (xy)^2)/(x^3*y^2)

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:

Hide Tags

Find Similar Topics 
Retired Moderator
User avatar
V
Joined: 27 Oct 2017
Posts: 1879
WE: General Management (Education)
GMAT ToolKit User CAT Tests
If xy ≠ 0, what is the value of (x^4*y^2- (xy)^2)/(x^3*y^2)  [#permalink]

Show Tags

New post Updated on: 04 Dec 2018, 06:02
00:00
A
B
C
D
E

Difficulty:

  15% (low)

Question Stats:

77% (01:09) correct 23% (01:09) wrong based on 211 sessions

HideShow timer Statistics

Project DS Butler: Day 28: Data Sufficiency (DS55)


For DS butler Questions Click Here


If \(xy\neq{0}\), what is the value of \(\frac{(x^4*y^2- (xy)^2)}{(x^3*y^2)}\)


(1) x = 2
(2) y = 8

_________________

Originally posted by GMATBusters on 04 Dec 2018, 05:57.
Last edited by Bunuel on 04 Dec 2018, 06:02, edited 1 time in total.
Renamed the topic and edited the question.
GMAT Club Legend
GMAT Club Legend
User avatar
V
Joined: 11 Sep 2015
Posts: 4999
Location: Canada
GMAT 1: 770 Q49 V46
If xy ≠ 0, what is the value of (x^4*y^2- (xy)^2)/(x^3*y^2)  [#permalink]

Show Tags

New post Updated on: 09 Apr 2020, 14:08
1
Top Contributor
gmatbusters wrote:
If \(xy\neq{0}\), what is the value of \(\frac{(x^4y^2- (xy)^2)}{(x^3y^2)}\)

(1) x = 2
(2) y = 8


Target question: What is the value of \(\frac{(x^4y^2- (xy)^2)}{(x^3y^2)}\)
This is a good candidate for rephrasing the target question.

\(\frac{(x^4y^2- (xy)^2)}{(x^3y^2)} = \frac{(x^4y^2- x^2y^2)}{(x^3y^2)}\)

\(= \frac{x^2y^2(x^2-1)}{(x^2y^2)(x)}\)

\(= \frac{x^2-1}{x}\)

REPHRASED target question: What is the value of \(\frac{x^2-1}{x}\)?

Aside: there’s a video below with tips on rephrasing the target question

Statement 1: x = 2
Since the REPHRASED target question involves only the value of x, we can simply plug x = 2 into the expression .
We get: \(\frac{x^2-1}{x}=\frac{2^2-1}{2}=\frac{3}{2}\)
Since we can answer the REPHRASED target question with certainty, statement 1 is SUFFICIENT

Statement 2: y = 8
Since the REPHRASED target question involves only the value of x, the value of y is of no use to us.
Statement 2 is NOT SUFFICIENT

Answer: A

VIDEO ON REPHRASING THE TARGET QUESTION

_________________
If you enjoy my solutions, you'll love my GMAT prep course.

Image

Originally posted by BrentGMATPrepNow on 04 Dec 2018, 06:59.
Last edited by BrentGMATPrepNow on 09 Apr 2020, 14:08, edited 1 time in total.
GMATH Teacher
User avatar
P
Status: GMATH founder
Joined: 12 Oct 2010
Posts: 938
If xy ≠ 0, what is the value of (x^4*y^2- (xy)^2)/(x^3*y^2)  [#permalink]

Show Tags

New post 04 Dec 2018, 18:51
gmatbusters wrote:

If \(xy\neq{0}\), what is the value of \(\frac{(x^4*y^2- (xy)^2)}{(x^3*y^2)}\)


(1) x = 2
(2) y = 8

\(x,y\,\, \ne 0\)

\(? = {{{x^2} \cdot {y^2} \cdot \left( {{x^2} - 1} \right)} \over {{x^2} \cdot {y^2} \cdot x}} = {{{x^2} - 1} \over x}\)


\(\left( 1 \right)\,\,x = 2\,\,\,\, \Rightarrow \,\,\,\,?\,\,\,{\rm{unique}}\)


\(\left( 2 \right)\,\,y = 8\,\,\left\{ \matrix{
\,{\rm{Take}}\,\,x = 1\,\,\,\, \Rightarrow \,\,\,? = 0 \hfill \cr
\,{\rm{Take}}\,\,x = 2\,\,\,\, \Rightarrow \,\,\,? \ne 0 \hfill \cr} \right.\)


The correct answer is therefore (A).


This solution follows the notations and rationale taught in the GMATH method.

Regards,
Fabio.
_________________
Fabio Skilnik :: GMATH method creator (Math for the GMAT)
Our high-level "quant" preparation starts here: https://gmath.net
Manager
Manager
User avatar
G
Joined: 07 Aug 2018
Posts: 104
Location: United States (MA)
GMAT 1: 560 Q39 V28
GMAT 2: 670 Q48 V34
Re: If xy ≠ 0, what is the value of (x^4*y^2- (xy)^2)/(x^3*y^2)  [#permalink]

Show Tags

New post 05 Dec 2018, 01:40
IMO A

But I rephrased the question stem in a slightly different way:

\(\frac{(x^4*y^2- (xy)^2)}{(x^3*y^2)}\) can be split in to fractions: \(\frac{x^4*y^2}{x^3*y^2}-\frac{(xy)^2}{x^3*y^2}\)

Simplify further: \(x-\frac{x^2*y^2}{x^3*y^2}\) \(=\) \(x-\frac{1}{x}\)

We only need the value of \(x\)...
_________________
Intern
Intern
User avatar
B
Joined: 15 Aug 2018
Posts: 49
GMAT 1: 740 Q47 V45
GPA: 3.5
Re: If xy ≠ 0, what is the value of (x^4*y^2- (xy)^2)/(x^3*y^2)  [#permalink]

Show Tags

New post 06 Dec 2018, 05:39
T1101 wrote:
IMO A

But I rephrased the question stem in a slightly different way:

\(\frac{(x^4*y^2- (xy)^2)}{(x^3*y^2)}\) can be split in to fractions: \(\frac{x^4*y^2}{x^3*y^2}-\frac{(xy)^2}{x^3*y^2}\)

Simplify further: \(x-\frac{x^2*y^2}{x^3*y^2}\) \(=\) \(x-\frac{1}{x}\)

We only need the value of \(x\)...


It seems to me that you went for the wrong approach here mate. It turns out that you can answer the question correctly by using your method, but this is just lucky here. You missed that the term in the numerator is in brackets, which is why your approach has no applicability here.

Best, LB
Manager
Manager
User avatar
G
Joined: 07 Aug 2018
Posts: 104
Location: United States (MA)
GMAT 1: 560 Q39 V28
GMAT 2: 670 Q48 V34
Re: If xy ≠ 0, what is the value of (x^4*y^2- (xy)^2)/(x^3*y^2)  [#permalink]

Show Tags

New post 06 Dec 2018, 06:33
gota900 wrote:
T1101 wrote:
IMO A

But I rephrased the question stem in a slightly different way:

\(\frac{(x^4*y^2- (xy)^2)}{(x^3*y^2)}\) can be split in to fractions: \(\frac{x^4*y^2}{x^3*y^2}-\frac{(xy)^2}{x^3*y^2}\)

Simplify further: \(x-\frac{x^2*y^2}{x^3*y^2}\) \(=\) \(x-\frac{1}{x}\)

We only need the value of \(x\)...


It seems to me that you went for the wrong approach here mate. It turns out that you can answer the question correctly by using your method, but this is just lucky here. You missed that the term in the numerator is in brackets, which is why your approach has no applicability here.

Best, LB


Why does it matter if the term in the numerator is in brackets? I can still split it since the denominator does not involve subraction or addition? Can you eloborate please?

Furhtermore I can reduce\(\frac{(x^2-1)}{x}\) into \(\frac{x^2}{x}-\frac{1}{x}\) --> \(x-\frac{1}{x}\), which is the same as with the oterh approach...

Kindly correct me if I am wrong
_________________
CEO
CEO
User avatar
V
Joined: 03 Jun 2019
Posts: 3362
Location: India
GMAT 1: 690 Q50 V34
WE: Engineering (Transportation)
Reviews Badge CAT Tests
If xy ≠ 0, what is the value of (x^4*y^2- (xy)^2)/(x^3*y^2)  [#permalink]

Show Tags

New post 24 May 2020, 05:41
GMATBusters wrote:

Project DS Butler: Day 28: Data Sufficiency (DS55)


For DS butler Questions Click Here


If \(xy\neq{0}\), what is the value of \(\frac{(x^4*y^2- (xy)^2)}{(x^3*y^2)}\)


(1) x = 2
(2) y = 8


Asked: If \(xy\neq{0}\), what is the value of \(\frac{(x^4*y^2- (xy)^2)}{(x^3*y^2)}\)
\(\frac{(x^4*y^2- (xy)^2)}{(x^3*y^2)} = x - \frac{1}{x} \)

(1) x = 2
\(\frac{(x^4*y^2- (xy)^2)}{(x^3*y^2)} = x - \frac{1}{x} = 2 - \frac{1}{2} = 1.5\)
SUFFICIENT

(2) y = 8
\(\frac{(x^4*y^2- (xy)^2)}{(x^3*y^2)} = x - \frac{1}{x} \) is independent of y
NOT SUFFICIENT

IMO A
_________________
Kinshook Chaturvedi
Email: kinshook.chaturvedi@gmail.com
GMAT Club Bot
If xy ≠ 0, what is the value of (x^4*y^2- (xy)^2)/(x^3*y^2)   [#permalink] 24 May 2020, 05:41

If xy ≠ 0, what is the value of (x^4*y^2- (xy)^2)/(x^3*y^2)

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  





Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne