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

 It is currently 19 May 2013, 17:32

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

Author Message
TAGS:
Manager
Joined: 24 Dec 2009
Posts: 229
Followers: 2

Kudos [?]: 19 [0], given: 3

If x is an integer, then is x a prime number? [#permalink]  04 May 2012, 20:51
00:00

Question Stats:

45% (01:33) correct 54% (00:21) wrong based on 0 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
GMAT Club team member
Joined: 02 Sep 2009
Posts: 11516
Followers: 1791

Kudos [?]: 9536 [0], given: 826

Re: If x is an integer, then is x a prime number? [#permalink]  04 May 2012, 21:38
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.

_________________
Manager
Joined: 18 Oct 2010
Posts: 82
Followers: 1

Kudos [?]: 55 [1] , given: 26

Re: If x is an integer, then is x a prime number? [#permalink]  05 May 2012, 17:01
1
KUDOS
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.

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
Re: If x is an integer, then is x a prime number?   [#permalink] 05 May 2012, 17:01
Similar topics Replies Last post
Similar
Topics:
Is the odd integer X a prime number? 1) X+2 is a prime 5 02 Jul 2004, 09:51
If x is a positive integer, is x! + (x + 1) a prime number? 2 30 Oct 2007, 10:28
If x is a positive integer, is x! + (x + 1) a prime number? 3 24 Dec 2007, 03:47
1 If x is an integer, is x a prime number? 1. x is a multiple 3 28 Feb 2008, 09:17
If x is a positive integer, is x! + (x + 1) a prime number ? 2 09 Mar 2008, 09:23
Display posts from previous: Sort by