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

 It is currently 14 Dec 2018, 11:25

### 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 December
PrevNext
SuMoTuWeThFrSa
2526272829301
2345678
9101112131415
16171819202122
23242526272829
303112345
Open Detailed Calendar
• ### Typical Day of a UCLA MBA Student - Recording of Webinar with UCLA Adcom and Student

December 14, 2018

December 14, 2018

10:00 PM PST

11:00 PM PST

Carolyn and Brett - nicely explained what is the typical day of a UCLA student. I am posting below recording of the webinar for those who could't attend this session.
• ### Free GMAT Strategy Webinar

December 15, 2018

December 15, 2018

07:00 AM PST

09:00 AM PST

Aiming to score 760+? Attend this FREE session to learn how to Define your GMAT Strategy, Create your Study Plan and Master the Core Skills to excel on the GMAT.

# If wxyz ≠ 0, does wxyz = 1? (1) w = 1/x, y = 1/z (2) wx^2 = 1/xyz

Author Message
TAGS:

### Hide Tags

Math Expert
Joined: 02 Sep 2009
Posts: 51215
If wxyz ≠ 0, does wxyz = 1? (1) w = 1/x, y = 1/z (2) wx^2 = 1/xyz  [#permalink]

### Show Tags

01 Aug 2018, 04:00
00:00

Difficulty:

35% (medium)

Question Stats:

73% (01:19) correct 27% (01:41) wrong based on 55 sessions

### HideShow timer Statistics

If $$wxyz ≠ 0$$, does $$wxyz = 1$$?

(1) $$w = \frac{1}{x}$$, $$y = \frac{1}{z}$$

(2) $$wx^2 = \frac{1}{xyz}$$

_________________
Intern
Joined: 10 Feb 2018
Posts: 13
Location: United States (TX)
Schools: McCombs '21 (I)
GMAT 1: 690 Q40 V44
GPA: 3.58
WE: Project Management (Computer Software)
Re: If wxyz ≠ 0, does wxyz = 1? (1) w = 1/x, y = 1/z (2) wx^2 = 1/xyz  [#permalink]

### Show Tags

01 Aug 2018, 19:24
Bunuel wrote:
If $$wxyz ≠ 0$$, does $$wxyz = 1$$?

(1) $$w = \frac{1}{x}$$, $$y = \frac{1}{z}$$

(2) $$wx^2 = \frac{1}{xyz}$$

Can someone please explain this one? I understand why A is sufficient, but for some reason I'm getting stuck on proving out (2) as insufficient

Thanks.
Director
Status: Learning stage
Joined: 01 Oct 2017
Posts: 931
WE: Supply Chain Management (Energy and Utilities)
If wxyz ≠ 0, does wxyz = 1? (1) w = 1/x, y = 1/z (2) wx^2 = 1/xyz  [#permalink]

### Show Tags

01 Aug 2018, 19:42
Bunuel wrote:
If $$wxyz ≠ 0$$, does $$wxyz = 1$$?

(1) $$w = \frac{1}{x}$$, $$y = \frac{1}{z}$$

(2) $$wx^2 = \frac{1}{xyz}$$

St1:- $$w = \frac{1}{x}$$, $$y = \frac{1}{z}$$
Substituting x and y in question stem, we have
wxyz=$$\frac{1}{x}*x*\frac{1}{z}*z$$=$$(\frac{1}{x}*x)*(\frac{1}{z}*z)$$=1*1=1
Sufficient.
St2:- $$wx^2 = \frac{1}{xyz}$$
Cross-multiplying,
$$wx^2*xyz =1$$
When x=w=y=z=1, then LHS=RHS=1. So, $$wxyz=1$$
When $$w=\frac{1}{8}$$,x=2,y=z=1, then LHS=RHS=1. So, $$wxyz=\frac{1}{8}*2*1*1={\frac{1}{4}}\neq1$$
Insufficient.

Ans. (A)
_________________

Regards,

PKN

Rise above the storm, you will find the sunshine

If wxyz ≠ 0, does wxyz = 1? (1) w = 1/x, y = 1/z (2) wx^2 = 1/xyz &nbs [#permalink] 01 Aug 2018, 19:42
Display posts from previous: Sort by