Find all School-related info fast with the new School-Specific MBA Forum

It is currently 23 Jul 2014, 06:28

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.

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

m01#23

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
Intern
Intern
avatar
Joined: 17 Oct 2008
Posts: 16
Followers: 0

Kudos [?]: 2 [0], given: 0

m01#23 [#permalink] New post 15 Nov 2008, 20:19
00:00
A
B
C
D
E

Difficulty:

  15% (low)

Question Stats:

82% (01:19) correct 18% (00:15) wrong based on 217 sessions
If Z is an integer, what is the value of Z ?

1. Z^2 \le 0
2. Z^3 \le 0

[Reveal] Spoiler: OA
A

Source: GMAT Club Tests - hardest GMAT questions

Does anyone has an explanation for A)
[Reveal] Spoiler: OA
Kaplan GMAT Prep Discount CodesKnewton GMAT Discount CodesVeritas Prep GMAT Discount Codes
SVP
SVP
avatar
Joined: 17 Jun 2008
Posts: 1580
Followers: 11

Kudos [?]: 174 [0], given: 0

GMAT Tests User
Re: m1#23 [#permalink] New post 16 Nov 2008, 09:33
GMAT scope includes only real numbers. Hence, from stmt1: Z will be real on if Z = 0. Hence, sufficient.
CEO
CEO
User avatar
Joined: 29 Aug 2007
Posts: 2501
Followers: 51

Kudos [?]: 482 [0], given: 19

GMAT Tests User
Re: m1#23 [#permalink] New post 16 Nov 2008, 15:45
rishi4you wrote:
If Z is an integer, what is the value of z


1) Z^2<=0 (read as z raised to the power 2 is less than equal to 0)
2) z^3<=0 (read as z raised to the power 3 is less than equal to 0)


A)Statement (1) ALONE is sufficient, but Statement (2) ALONE is not sufficient
B)Statement (2) ALONE is sufficient, but Statement (1) ALONE is not sufficient
C)BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient
D)EACH statement ALONE is sufficient
E)Statements (1) and (2) TOGETHER are NOT sufficient

Does anyone has an explanation for A)


A. z = 0.
1: z cannot be -ve. so it has to be 0. suff.
2: z can be -ve or 0. so nsf..

_________________

Verbal: new-to-the-verbal-forum-please-read-this-first-77546.html
Math: new-to-the-math-forum-please-read-this-first-77764.html
Gmat: everything-you-need-to-prepare-for-the-gmat-revised-77983.html


GT

Manager
Manager
avatar
Joined: 21 Sep 2008
Posts: 78
Location: Atlanta, Georgia
Schools: Georgetown, UNC, Emory, GeorgiaTech
WE 1: Product Engineering
WE 2: Logistics & Inventory
WE 3: Product Information & Pricing Manager
Followers: 2

Kudos [?]: 2 [0], given: 0

Re: m1#23 [#permalink] New post 16 Nov 2008, 18:54
I guess you already have your answer but I'll just type it out thoroughly.

(a) notes that square of a number is less than or equal to zero. You know that square of any positive or negative integer is positive, so the value cannot be less than 0. So only answer is "zero". Sufficient.

(b) notes that raised to 3 power is less than or equal to 0. 0x0x0 = true, -1x-1x-1 is less than 0 = true. You have multiple values, so this one is insufficient.

Hence the answer is A.
Intern
Intern
avatar
Joined: 23 Jul 2010
Posts: 18
Location: New York
Schools: Booth, Columbia, Ross, Kellogg
Followers: 0

Kudos [?]: 9 [0], given: 11

Re: m01#23 [#permalink] New post 21 Sep 2010, 05:11
it's A.

given that Z is an integer , so Z Sq cannot be negative. It has to be 0.Sufficient

When Z power 3 is -ve , it could be any -ve integer. not Sufficient.
Manager
Manager
User avatar
Status: He who asks is a fool for five minutes, but he who does not ask remains a fool forever
Joined: 20 Aug 2010
Posts: 102
Followers: 2

Kudos [?]: 2 [0], given: 2

Re: m01#23 [#permalink] New post 21 Sep 2010, 05:26
As per the equation one we have Z^2 <=0 that means either Z is 0 or not real. In case of GMAT we only need to consider real numbers . So A is sufficient.

As per B we have Z^3 <= 0 , so Z can be either 0 or negative , therefore we dont have unique answer .So B is not sufficient

Therefore A is the answer.
Senior Manager
Senior Manager
User avatar
Joined: 25 Jul 2010
Posts: 300
Location: India
Concentration: Strategy, Technology
GMAT 1: 770 Q51 V46
GPA: 3.2
WE: Engineering (Computer Software)
Followers: 17

Kudos [?]: 28 [0], given: 20

GMAT Tests User Reviews Badge
Re: m01#23 [#permalink] New post 21 Sep 2010, 05:37
For any integer Z, Z^2 is always positive, ie Z^2 >= 0
(1) states that Z^2 <= 0

Thus we can figure that Z^2 = 0, ie Z=0

Z^3 can have positive and negative values
(2) states that Z^3 <= 0
For z=0, Z^3 = 0
For z=-1, Z^3 = -1, both are <=0, therefore we cannot reach a conclusion.
Intern
Intern
avatar
Joined: 30 Aug 2010
Posts: 23
Followers: 0

Kudos [?]: 0 [0], given: 2

Re: m01#23 [#permalink] New post 21 Sep 2010, 05:57
Is it me, or have the past few quant questions of the day (including this one) been far too easy?

I don't mean to sound high and mighty. I mean I know that I am at a 600-700 level for quant, so these should be pretty challenging for me, but the last few have not been. Thoughts?
Intern
Intern
avatar
Joined: 07 Jan 2010
Posts: 2
Followers: 0

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

Reviews Badge
Re: m01#23 [#permalink] New post 21 Sep 2010, 06:28
Its A.
1. Squares are non-negative. So Z is 0
2. Z can be 0 or negative number
Intern
Intern
avatar
Joined: 07 Sep 2010
Posts: 4
Followers: 0

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

Re: m01#23 [#permalink] New post 21 Sep 2010, 07:16
Z must be an integer rules out imaginary numbers.

Zsquared must be positive but cannot due to z <= 0 limit so Z must be zero. Suff

Zcubed allows for negative numbers. Insuff.
Intern
Intern
avatar
Joined: 02 Jun 2010
Posts: 3
Followers: 0

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

Re: m01#23 [#permalink] New post 21 Sep 2010, 18:15
A : if and only if Z=0 : OK
B : any integer that satisfies Z<=0 : so NG

IMO - A
Manager
Manager
avatar
Joined: 28 Oct 2009
Posts: 95
Followers: 1

Kudos [?]: 8 [0], given: 42

Re: m01#23 [#permalink] New post 22 Sep 2010, 11:21
After asking google whether zero was an integer, I brilliantly chose A.
Manager
Manager
avatar
Joined: 30 May 2010
Posts: 191
Followers: 3

Kudos [?]: 41 [0], given: 32

GMAT Tests User
Re: m1#23 [#permalink] New post 22 Sep 2010, 12:49
GaryDunn wrote:
GMAT TIGER wrote:
rishi4you wrote:
If Z is an integer, what is the value of z


1) Z^2<=0 (read as z raised to the power 2 is less than equal to 0)
2) z^3<=0 (read as z raised to the power 3 is less than equal to 0)


A)Statement (1) ALONE is sufficient, but Statement (2) ALONE is not sufficient
B)Statement (2) ALONE is sufficient, but Statement (1) ALONE is not sufficient
C)BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient
D)EACH statement ALONE is sufficient
E)Statements (1) and (2) TOGETHER are NOT sufficient

Does anyone has an explanation for A)


A. z = 0.
1: z cannot be -ve. so it has to be 0. suff.
2: z can be -ve or 0. so nsf..



Can someone explain the ve/-ve notation please.


I think it is shorthand (laziness?) for positive (+ve) and negative (-ve).
Director
Director
avatar
Joined: 21 Dec 2009
Posts: 588
Concentration: Entrepreneurship, Finance
Followers: 15

Kudos [?]: 230 [0], given: 20

GMAT Tests User
Re: m01#23 [#permalink] New post 22 Sep 2010, 23:24
I don't think i have a better explanation than what have been given above.
Generally, if x^2<0, then x must be an invalid number on the number line.
x must be 0, A is sufficient.

_________________

KUDOS me if you feel my contribution has helped you.

Manager
Manager
User avatar
Joined: 01 Nov 2010
Posts: 194
Location: India
Concentration: Technology, Marketing
GMAT Date: 08-27-2012
GPA: 3.8
WE: Marketing (Manufacturing)
Followers: 5

Kudos [?]: 19 [0], given: 26

GMAT Tests User
Re: m01#23 [#permalink] New post 23 Sep 2011, 03:54
easy one.

Statement 1 is sufficient to answer the question.

keep in mind that GMAT never ask for Imaginary numbers. it works on Real No only.

_________________

kudos me if you like my post.

Attitude determine everything.
all the best and God bless you.

Current Student
User avatar
Joined: 16 Sep 2010
Posts: 227
Location: United States
Concentration: Finance, Real Estate
GMAT 1: 740 Q48 V42
Followers: 7

Kudos [?]: 56 [0], given: 2

GMAT Tests User
Re: m01#23 [#permalink] New post 14 Nov 2011, 21:21
Statement 1 tells us that Z must be equal to zero.

Statement 2 tells us that Z can be either zero or any negative integer.


So statement 1 is sufficient, statement 2 is insufficient. Ans -A.
Manager
Manager
avatar
Joined: 07 Sep 2011
Posts: 74
GMAT 1: 660 Q41 V40
GMAT 2: 720 Q49 V39
WE: Analyst (Mutual Funds and Brokerage)
Followers: 1

Kudos [?]: 21 [0], given: 13

Re: m01#23 [#permalink] New post 25 Sep 2012, 05:31
1) Z^2 will always be a NON-NEGATIVE number. Therefore, if Z^2<=0, this means that |z|<=0. Because it cannot be negative, it must be 0. SUFFICIENT.

2) Z^3 can be a negative or positive or 0. if Z^3 <=0, it could be any number equal or less than 0. INSUFFICIENT.

Answer is A.
Intern
Intern
avatar
Status: At the end all are winners, Some just take a little more time to win.
Joined: 08 Oct 2013
Posts: 23
Location: India
Concentration: Finance, Accounting
GMAT Date: 11-20-2013
GPA: 3.97
WE: Consulting (Computer Software)
Followers: 0

Kudos [?]: 7 [0], given: 45

Re: m01#23 [#permalink] New post 29 Oct 2013, 04:50
Not sure if this question is correct; Bunuel / some one else can u please clarify me here.

According to first statement z=0 is being taken; but 0*0 will give undefined so how can we equate it to zero.

Pls help
Expert Post
1 KUDOS received
Math Expert
User avatar
Joined: 02 Sep 2009
Posts: 18693
Followers: 3234

Kudos [?]: 22248 [1] , given: 2602

Re: m01#23 [#permalink] New post 29 Oct 2013, 05:52
1
This post received
KUDOS
Expert's post
amkabdul wrote:
Not sure if this question is correct; Bunuel / some one else can u please clarify me here.

According to first statement z=0 is being taken; but 0*0 will give undefined so how can we equate it to zero.

Pls help


Division by 0 is undefined: number/0=undefined but 0*0=0.

Hope it helps.

_________________

NEW TO MATH FORUM? PLEASE READ THIS: ALL YOU NEED FOR QUANT!!!

PLEASE READ AND FOLLOW: 11 Rules for Posting!!!

RESOURCES: [GMAT MATH BOOK]; 1. Triangles; 2. Polygons; 3. Coordinate Geometry; 4. Factorials; 5. Circles; 6. Number Theory; 7. Remainders; 8. Overlapping Sets; 9. PDF of Math Book; 10. Remainders; 11. GMAT Prep Software Analysis NEW!!!; 12. SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) NEW!!!; 12. Tricky questions from previous years. NEW!!!;

COLLECTION OF QUESTIONS:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS ; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


What are GMAT Club Tests?
25 extra-hard Quant Tests

Get the best GMAT Prep Resources with GMAT Club Premium Membership

Re: m01#23   [#permalink] 29 Oct 2013, 05:52
Display posts from previous: Sort by

m01#23

  Question banks Downloads My Bookmarks Reviews Important topics  

Moderators: Bunuel, WoundedTiger



GMAT Club MBA Forum Home| About| Privacy Policy| Terms and Conditions| GMAT Club Rules| Contact| Sitemap

Powered by phpBB © phpBB Group and phpBB SEO

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®.