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

 It is currently 20 Aug 2018, 09:40

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

If x is an integer, is x a prime number? 1. x is a multiple

Author Message
VP
Joined: 30 Jun 2008
Posts: 1004
If x is an integer, is x a prime number? 1. x is a multiple  [#permalink]

Show Tags

30 Sep 2008, 10:58
00:00

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 0 sessions

HideShow timer Statistics

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

1. $$x$$ is a multiple of a prime number
2. $$x$$ is a product of two integers

if x is a multiple of a prime number, doesn't it mean that x is NOT prime. isn't the first statement alone sufficient ? Am I missing something ??

--== Message from GMAT Club Team ==--

This is not a quality discussion. It has been retired.

If you would like to discuss this question please re-post it in the respective forum. Thank you!

To review the GMAT Club's Forums Posting Guidelines, please follow these links: Quantitative | Verbal Please note - we may remove posts that do not follow our posting guidelines. Thank you.

_________________

"You have to find it. No one else can find it for you." - Bjorn Borg

VP
Joined: 17 Jun 2008
Posts: 1474
Re: DS: Is x prime ?  [#permalink]

Show Tags

30 Sep 2008, 11:29
[quote="amitdgr"]If $$x$$ is an integer, is $$x$$ a prime number?

1. $$x$$ is a multiple of a prime number
2. $$x$$ is a product of two integers

if x is a multiple of a prime number, doesn't it mean that x is NOT prime. isn't the first statement alone sufficient ? Am I missing something ??[/quote]

A prime number is a multiple of itself. That is the reason, stmt1 cannot be sufficient.

From stmt1, x can be 2,3, 4,5, 6,7,8,9,10,11.......and hence not sufficient as x can be a prime or a non-prime.

From stmt2, again x can be anything (e.g. 2 = 2*1, 3 = 3*1, and so on).

Hence, to me, the answer should be E.
Director
Joined: 23 May 2008
Posts: 739
Re: DS: Is x prime ?  [#permalink]

Show Tags

30 Sep 2008, 11:32
i think the answer is E

1) x is a multiple of a prime

2 is the first multiple of 2: 2 is prime
4 is the second multiple of 2: 4 is not prime
insuff

2) x is a product of 2 int.

2*1 is prime
2*2 is not prime

together insufficient
same reasons as stmnt 2
SVP
Joined: 29 Aug 2007
Posts: 2419
Re: DS: Is x prime ?  [#permalink]

Show Tags

30 Sep 2008, 11:44
scthakur wrote:
amitdgr wrote:
If $$x$$ is an integer, is $$x$$ a prime number?

1. $$x$$ is a multiple of a prime number
2. $$x$$ is a product of two integers

if x is a multiple of a prime number, doesn't it mean that x is NOT prime. isn't the first statement alone sufficient ? Am I missing something ??

A prime number is a multiple of itself. That is the reason, stmt1 cannot be sufficient.

From stmt1, x can be 2,3, 4,5, 6,7,8,9,10,11.......and hence not sufficient as x can be a prime or a non-prime.

From stmt2, again x can be anything (e.g. 2 = 2*1, 3 = 3*1, and so on).

Hence, to me, the answer should be E.

FROM 1: X can be any integer > 1.
FROM 2: X can be any integer.

neither each alone nor togather is sufficient to answer.

//E//
_________________

Gmat: http://gmatclub.com/forum/everything-you-need-to-prepare-for-the-gmat-revised-77983.html

GT

Director
Joined: 25 Oct 2006
Posts: 587
Re: DS: Is x prime ?  [#permalink]

Show Tags

30 Sep 2008, 11:45
IMO E.

1. Consider x = 3, so multiple of 3 and PRIME ...
Consider x=6, not a prime....
1 is insuff

2. Consider x=3, product of two integers 1 and 3.
COnsider x=6, product of two integers 2 and 3
2 in insuff

SO A, D, B are out and left with C and E

Lets consider x=3 and x=6 again. suffice and insuffice for 1 and 2. Hence E.
_________________

If You're Not Living On The Edge, You're Taking Up Too Much Space

VP
Joined: 30 Jun 2008
Posts: 1004
Re: DS: Is x prime ?  [#permalink]

Show Tags

30 Sep 2008, 20:10
OA is E. Thank you for explanation guys ! I fell into the trap designed in this question.

--== Message from GMAT Club Team ==--

This is not a quality discussion. It has been retired.

If you would like to discuss this question please re-post it in the respective forum. Thank you!

To review the GMAT Club's Forums Posting Guidelines, please follow these links: Quantitative | Verbal Please note - we may remove posts that do not follow our posting guidelines. Thank you.

_________________

"You have to find it. No one else can find it for you." - Bjorn Borg

Re: DS: Is x prime ? &nbs [#permalink] 30 Sep 2008, 20:10
Display posts from previous: Sort by

Events & Promotions

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