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

It is currently 01 Jul 2015, 05:17

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

If x is an integer, then is x a prime number?

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
Manager
Manager
avatar
Joined: 24 Dec 2009
Posts: 227
Followers: 2

Kudos [?]: 32 [0], given: 3

If x is an integer, then is x a prime number? [#permalink] New post 04 May 2012, 19:51
00:00
A
B
C
D
E

Difficulty:

  55% (hard)

Question Stats:

51% (01:35) correct 49% (00:23) wrong based on 50 sessions
If x is an integer, then is x a prime number?

(1) x is a multiple of a prime number.
(2) x is a product of two integers.
[Reveal] Spoiler: OA
Expert Post
Math Expert
User avatar
Joined: 02 Sep 2009
Posts: 28224
Followers: 4457

Kudos [?]: 44920 [0], given: 6634

Re: If x is an integer, then is x a prime number? [#permalink] New post 04 May 2012, 20:38
Expert's post
If x is an integer, then is x a prime number?

(1) x is a multiple of a prime number --> if x=2 then the asnwer is Yes, but if x=4 then the answer is NO. Not sufficient.

(2) x is a product of two integers --> the same here: if x=1*2=2 then the asnwer is Yes, but if x=1*4=4 then the answer is NO. Not sufficient.

(1)+(2) The same xample: if x=2 then the asnwer is Yes, but if x=4 then the answer is NO. Not sufficient.

Answer: E.
_________________

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

GMAT Club Premium Membership - big benefits and savings

1 KUDOS received
Manager
Manager
avatar
Joined: 17 Oct 2010
Posts: 79
Followers: 1

Kudos [?]: 97 [1] , given: 26

Re: If x is an integer, then is x a prime number? [#permalink] New post 05 May 2012, 16:01
1
This post received
KUDOS
1
This post was
BOOKMARKED
Bunuel wrote:
If x is an integer, then is x a prime number?

(1) x is a multiple of a prime number --> if x=2 then the asnwer is Yes, but if x=4 then the answer is NO. Not sufficient.

(2) x is a product of two integers --> the same here: if x=1*2=2 then the asnwer is Yes, but if x=1*4=4 then the answer is NO. Not sufficient.

(1)+(2) The same xample: if x=2 then the asnwer is Yes, but if x=4 then the answer is NO. Not sufficient.

Answer: E.


let me just further elaborate on Bunuel
(1) let the prime number be 2 then 2*1= 2 this is a prime number
again 2*2 =4 this is not a prime number so both 2 and 4 are multiples of the prime number 2, but 2 is a prime number and 4 is not so (1) is not sufficient


similarly 6 is a product of 2 integers 3*2 and 6 is not a prime number
but 2 is also a multiple of 2 integers 1*2 and 2 is a prime number
so (2) is also not sufficient

Taking both (1) and (2)
First number 2 , (1) Is a multiple of a prime no.( 2*1)
(2) is the product of 2 integers (2*1)
and 2 is a prime number

second number 6, (1) Is a multiple of a prime no.( 3*2)
(2) is the product of 2 integers (3*2)

and 6 is not a prime number

as both 1 and 2 together do not give a consistent answer the answer is e

Hope I have understood it correctly ,

Thanks Bunuel
Manager
Manager
User avatar
Status: Kitchener
Joined: 03 Oct 2013
Posts: 101
Location: Canada
Concentration: Finance, Finance
GPA: 2.9
WE: Education (Education)
Followers: 0

Kudos [?]: 18 [0], given: 144

Premium Member
If x is an integer, then is x a prime number? [#permalink] New post 06 Feb 2015, 08:26
Bunuel wrote:
If x is an integer, then is x a prime number?

(1) x is a multiple of a prime number --> if x=2 then the asnwer is Yes, but if x=4 then the answer is NO. Not sufficient.

(2) x is a product of two integers --> the same here: if x=1*2=2 then the asnwer is Yes, but if x=1*4=4 then the answer is NO. Not sufficient.

(1)+(2) The same xample: if x=2 then the asnwer is Yes, but if x=4 then the answer is NO. Not sufficient.

Answer: E.

Dear Bunuel, Ireally confused here in statement 1 (x is a multiple of a prime number )

in the case 2*1= 2. where is x here ? does it is 1 or 2 ?

Does the statement 1 mean that 2k=x? where k any integre.
_________________

Click +1 Kudos if my post helped

Expert Post
1 KUDOS received
Math Expert
User avatar
Joined: 02 Sep 2009
Posts: 28224
Followers: 4457

Kudos [?]: 44920 [1] , given: 6634

Re: If x is an integer, then is x a prime number? [#permalink] New post 06 Feb 2015, 08:36
1
This post received
KUDOS
Expert's post
23a2012 wrote:
Bunuel wrote:
If x is an integer, then is x a prime number?

(1) x is a multiple of a prime number --> if x=2 then the asnwer is Yes, but if x=4 then the answer is NO. Not sufficient.

(2) x is a product of two integers --> the same here: if x=1*2=2 then the asnwer is Yes, but if x=1*4=4 then the answer is NO. Not sufficient.

(1)+(2) The same xample: if x=2 then the asnwer is Yes, but if x=4 then the answer is NO. Not sufficient.

Answer: E.

Dear Bunuel, Ireally confused here in statement 1 (x is a multiple of a prime number )

in the case 2*1= 2. where is x here ? does it is 1 or 2 ?

Does the statement 1 mean that 2k=x? where k any integre.


x is a multiple of a prime number --> x = prime*k = 2*1.
_________________

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

GMAT Club Premium Membership - big benefits and savings

Manager
Manager
User avatar
Status: Kitchener
Joined: 03 Oct 2013
Posts: 101
Location: Canada
Concentration: Finance, Finance
GPA: 2.9
WE: Education (Education)
Followers: 0

Kudos [?]: 18 [0], given: 144

Premium Member
Re: If x is an integer, then is x a prime number? [#permalink] New post 06 Feb 2015, 08:44
Thank you Bunuel +1 KUDOS
_________________

Click +1 Kudos if my post helped

Re: If x is an integer, then is x a prime number?   [#permalink] 06 Feb 2015, 08:44
    Similar topics Author Replies Last post
Similar
Topics:
14 Experts publish their posts in the topic If x and y are positive integers, is x a prime number? bekerman 8 22 May 2014, 16:42
6 Experts publish their posts in the topic If x is a positive integer, is x! + (x + 1) a prime number? iamba 18 16 Jul 2007, 16:19
If x is a positive integer, is x! + (x + 1) a prime number? dynamo 3 24 Dec 2007, 02:47
If x is a positive integer, is x! + (x + 1) a prime number? jimjohn 2 30 Oct 2007, 09:28
Display posts from previous: Sort by

If x is an integer, then is x a prime number?

  Question banks Downloads My Bookmarks Reviews Important topics  


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®.