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

It is currently 28 Feb 2020, 21:07

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

What is x?

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

Hide Tags

Find Similar Topics 
Intern
Intern
avatar
Joined: 26 Jul 2016
Posts: 28
Location: India
Concentration: Operations, Entrepreneurship
Schools: Tepper '19
GPA: 3.69
WE: Analyst (Manufacturing)
What is x?  [#permalink]

Show Tags

New post Updated on: 16 Oct 2016, 11:58
4
00:00
A
B
C
D
E

Difficulty:

  35% (medium)

Question Stats:

67% (01:30) correct 33% (01:02) wrong based on 315 sessions

HideShow timer Statistics

What is x?

(1) x = 4y − 4
(2) xy = 8

Originally posted by yashrakhiani on 14 Oct 2016, 12:20.
Last edited by Bunuel on 16 Oct 2016, 11:58, edited 2 times in total.
Renamed the topic and added the OA.
Intern
Intern
User avatar
Joined: 24 Jun 2016
Posts: 30
GMAT ToolKit User
Re: What is x?  [#permalink]

Show Tags

New post 14 Oct 2016, 15:12
Answer is E

EXPLANATION
Statement I & II individually will not be able to answer as both have 2 variable and 1equation.

Hence option A,B,&D are ELIMINATED

now checking for..
answer option C

Solving together
From i) x=4y-4
ii) y=8/x using this
We get x^2 + 4x - 32 = 0
(x+8)(x-4)=0
I.E x= -8, +4
Hence 2 solution
We do not have a definite value of x

Hence answer option E is correct


Sent from my MotoG3 using GMAT Club Forum mobile app
Intern
Intern
User avatar
Joined: 24 Jun 2016
Posts: 30
GMAT ToolKit User
Re: What is x?  [#permalink]

Show Tags

New post 14 Oct 2016, 15:13
Consider giving me kudos if you got clarity on how to approach the question.

Sent from my MotoG3 using GMAT Club Forum mobile app
GMAT Club Legend
GMAT Club Legend
User avatar
V
Joined: 11 Sep 2015
Posts: 4360
Location: Canada
Re: What is x?  [#permalink]

Show Tags

New post 16 Oct 2016, 07:41
2
Top Contributor
yashrakhiani wrote:
What is x?

(1) x = 4y − 4
(2) xy = 8


Target question: What is the value of x?

Statement 1: x = 4y − 4
1 equation with 2 variables means there are infinitely many possible values for x.
If we're uncertain, we can TEST some values.
There are several values of x and y that satisfy statement 1. Here are two:
Case a: x = 0 and y = 1. in this case x = 0
Case b: x = 4 and y = 2. in this case x = 4
Since we cannot answer the target question with certainty, statement 1 is NOT SUFFICIENT

Statement 2: xy = 8
1 equation with 2 variables means there are infinitely many possible values for x.
If we're uncertain, we can TEST some values.
There are several values of x and y that satisfy statement 2. Here are two:
Case a: x = 1 and y = 8. in this case x = 1
Case b: x = 4 and y = 2. in this case x = 4
Since we cannot answer the target question with certainty, statement 2 is NOT SUFFICIENT

Statements 1 and 2 combined
Statement 1 tells us that x = 4y − 4
Statement 2 tells us that xy = 8

Take x = 4y − 4, and solve for y.
So, add 4 to both sides to get: x + 4 = 4y
Divide both sides by 4 to get: (x + 4)/4 = y

Now take xy = 8 and replace y with (x + 4)/4 to get...
(x)(x + 4)/4 = 8
Multiply both sides by 4 to get: (x)(x + 4) = 32
Expand: x² + 4x = 32
Set equal to zero to get: x² + 4x - 32 = 0
Factor: (x + 8)(x - 4) = 0
So, EITHER x = -8 OR x = 4
Since we cannot answer the target question with certainty, the combined statements are NOT SUFFICIENT

Answer:

RELATED VIDEOS



_________________
Test confidently with gmatprepnow.com
Image
Intern
Intern
avatar
Joined: 30 Sep 2016
Posts: 7
Re: What is x?  [#permalink]

Show Tags

New post 07 Dec 2016, 14:13
Can we not do this: x=4y-4

x=4(y-1) ie x = 4?
Manager
Manager
User avatar
P
Joined: 13 Jun 2012
Posts: 195
Location: United States
WE: Supply Chain Management (Computer Hardware)
GMAT ToolKit User
What is x?  [#permalink]

Show Tags

New post 07 Dec 2016, 15:52
Nasahtahir wrote:
Can we not do this: x=4y-4

x=4(y-1) ie x = 4?


No Sir, we cant. you mentioned correctly x=4(y-1), so to find X we have to know y. If you see some of the previous posts you will find the way .
Director
Director
avatar
S
Joined: 12 Nov 2016
Posts: 678
Location: United States
Schools: Yale '18
GMAT 1: 650 Q43 V37
GRE 1: Q157 V158
GPA: 2.66
Re: What is x?  [#permalink]

Show Tags

New post 08 Sep 2017, 20:34
yashrakhiani wrote:
What is x?

(1) x = 4y − 4
(2) xy = 8


So this question is actually a "C" trap

St 1

Clearly too many options

Insuff

St 2

Clearly too many options insuff

St 1 & 2

If x + 4 =4y and xy= 8 then

x + 4 (x) =32

X= 4 or -8

Insuff

E
Non-Human User
User avatar
Joined: 09 Sep 2013
Posts: 14156
Re: What is x?  [#permalink]

Show Tags

New post 18 Jan 2020, 07:17
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.
_________________
GMAT Club Bot
Re: What is x?   [#permalink] 18 Jan 2020, 07:17
Display posts from previous: Sort by

What is x?

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





cron

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