Is x a prime number? : GMAT Data Sufficiency (DS)
Check GMAT Club Decision Tracker for the Latest School Decision Releases http://gmatclub.com/AppTrack

 It is currently 19 Jan 2017, 06:15

# LIVE NOW:

Chat with Admission Manager and Current Student of NUS SIngapore - Join Chat Room to Participate.

### 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 June
Open Detailed Calendar

# Is x a prime number?

Author Message
TAGS:

### Hide Tags

Director
Joined: 29 Nov 2012
Posts: 898
Followers: 14

Kudos [?]: 1044 [0], given: 543

Is x a prime number? [#permalink]

### Show Tags

20 Dec 2012, 00:16
2
This post was
BOOKMARKED
00:00

Difficulty:

45% (medium)

Question Stats:

53% (01:46) correct 47% (00:36) wrong based on 180 sessions

### HideShow timer Statistics

Is x a prime number?

(1) x is an even number.
(2) x can not be divided evenly by an odd number other than 1.

can someone please explain statement 2
[Reveal] Spoiler: OA

_________________

Click +1 Kudos if my post helped...

Amazing Free video explanation for all Quant questions from OG 13 and much more http://www.gmatquantum.com/og13th/

GMAT Prep software What if scenarios http://gmatclub.com/forum/gmat-prep-software-analysis-and-what-if-scenarios-146146.html

VP
Status: Been a long time guys...
Joined: 03 Feb 2011
Posts: 1420
Location: United States (NY)
Concentration: Finance, Marketing
GPA: 3.75
Followers: 175

Kudos [?]: 1335 [0], given: 62

Re: Is x a prime number? [#permalink]

### Show Tags

20 Dec 2012, 00:34
Statement 2 states that x is not evenly divisible by an odd number other than 1.
It talks, IMO, about numbers such as 2, 4, 8, 10 etc i.e. multiples of 2 that are not divisible by ANY odd number but 1.
_________________
Math Expert
Joined: 02 Sep 2009
Posts: 36554
Followers: 7078

Kudos [?]: 93171 [1] , given: 10553

Re: Is x a prime number? [#permalink]

### Show Tags

20 Dec 2012, 01:14
1
KUDOS
Expert's post
Marcab wrote:
Statement 2 states that x is not evenly divisible by an odd number other than 1.
It talks, IMO, about numbers such as 2, 4, 8, 10 etc i.e. multiples of 2 that are not divisible by ANY odd number but 1.

10 is divisible by 5 so x cannot be 10.

Is x a prime number?

(1) x is an even number. If x=2 then the answer is YES but if x is any other even number then the answer is NO. Not sufficient.

(2) x can not be divided evenly by an odd number other than 1. This statement implies that x is some power of 2: 2, 4, 8, 16, ... Not sufficient.

(1)+(2) Still not sufficient. Consider x=2 and x=4.

_________________
VP
Status: Been a long time guys...
Joined: 03 Feb 2011
Posts: 1420
Location: United States (NY)
Concentration: Finance, Marketing
GPA: 3.75
Followers: 175

Kudos [?]: 1335 [0], given: 62

Re: Is x a prime number? [#permalink]

### Show Tags

20 Dec 2012, 01:20
yeah right.
missed it completely.
_________________
Current Student
Joined: 21 Oct 2013
Posts: 194
Location: Germany
GMAT 1: 660 Q45 V36
GPA: 3.51
Followers: 1

Kudos [?]: 37 [0], given: 19

Re: Is x a prime number? [#permalink]

### Show Tags

31 Jul 2014, 01:32
1
This post was
BOOKMARKED
This is more of a "don't overthink too much question" than anything else.
is x prime?

(1) x is even. X could be 2, hence prime. But also 4,6,8,...IS
(2) x can not be divided evenly by an odd number other than 1. This is tempting but the statement says nothing about even numbers. So x could be even! (I see what you did there).

Together it basically stays the same. From (2), x could be be even and from (1) we only get that x is even, hence still IS.

E.
GMAT Club Legend
Joined: 09 Sep 2013
Posts: 13447
Followers: 575

Kudos [?]: 163 [0], given: 0

Re: Is x a prime number? [#permalink]

### Show Tags

18 Dec 2015, 11:16
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________
Math Revolution GMAT Instructor
Joined: 16 Aug 2015
Posts: 2602
GPA: 3.82
Followers: 172

Kudos [?]: 1435 [1] , given: 0

Re: Is x a prime number? [#permalink]

### Show Tags

19 Dec 2015, 04:48
1
KUDOS
Expert's post
Forget conventional ways of solving math questions. In DS, Variable approach is the easiest and quickest way to find the answer without actually solving the problem. Remember equal number of variables and independent equations ensures a solution.

Is x a prime number?

(1) x is an even number.
(2) x can not be divided evenly by an odd number other than 1.

In the original condition, there is 1 variable(x), which should match with the number equation. So you need 1 more equation. However, for 1) 1 equation, for 2) 1 equation, which is likely to make D the answer.
In 1), x=2 -> yes and x=4 -> no, which is not sufficient.
In 2), x=2 -> yes and x=4 -> no, which is not sufficient. Even when 1) & 2), ), x=2 -> yes and x=4 -> no, which is not sufficient. Therefore, the answer is E.

-> For cases where we need 1 more equation, such as original conditions with “1 variable”, or “2 variables and 1 equation”, or “3 variables and 2 equations”, we have 1 equation each in both 1) and 2). Therefore, there is 59 % chance that D is the answer, while A or B has 38% chance and C or E has 3% chance. Since D is most likely to be the answer using 1) and 2) separately according to DS definition. Obviously there may be cases where the answer is A, B, C or E.
_________________

MathRevolution: Finish GMAT Quant Section with 10 minutes to spare
The one-and-only World’s First Variable Approach for DS and IVY Approach for PS with ease, speed and accuracy.
Find a 10% off coupon code for GMAT Club members.
“Receive 5 Math Questions & Solutions Daily”
Unlimited Access to over 120 free video lessons - try it yourself

Intern
Joined: 02 Nov 2015
Posts: 24
Followers: 0

Kudos [?]: 1 [0], given: 9

Re: Is x a prime number? [#permalink]

### Show Tags

01 Sep 2016, 02:20
Bunuel wrote:
Marcab wrote:
Statement 2 states that x is not evenly divisible by an odd number other than 1.
It talks, IMO, about numbers such as 2, 4, 8, 10 etc i.e. multiples of 2 that are not divisible by ANY odd number but 1.

10 is divisible by 5 so x cannot be 10.

Is x a prime number?

(1) x is an even number. If x=2 then the answer is YES but if x is any other even number then the answer is NO. Not sufficient.

(2) x can not be divided evenly by an odd number other than 1. This statement implies that x is some power of 2: 2, 4, 8, 16, ... Not sufficient.

(1)+(2) Still not sufficient. Consider x=2 and x=4.

Bunuel,

When we say - divide "evenly"- do we mean that the number should be divided in even factors? for example 9 (an odd) number can be divided by 3 bit there is no even factor. so, can we say that 3 divides 9 evenly? or only when a number has an even factor then we can say that number is "evenly" divided? Answer to this question will play a major role in solving above question.

Regards
Yash
Math Expert
Joined: 02 Sep 2009
Posts: 36554
Followers: 7078

Kudos [?]: 93171 [0], given: 10553

Re: Is x a prime number? [#permalink]

### Show Tags

01 Sep 2016, 02:25
Yash26 wrote:
Bunuel wrote:
Marcab wrote:
Statement 2 states that x is not evenly divisible by an odd number other than 1.
It talks, IMO, about numbers such as 2, 4, 8, 10 etc i.e. multiples of 2 that are not divisible by ANY odd number but 1.

10 is divisible by 5 so x cannot be 10.

Is x a prime number?

(1) x is an even number. If x=2 then the answer is YES but if x is any other even number then the answer is NO. Not sufficient.

(2) x can not be divided evenly by an odd number other than 1. This statement implies that x is some power of 2: 2, 4, 8, 16, ... Not sufficient.

(1)+(2) Still not sufficient. Consider x=2 and x=4.

Bunuel,

When we say - divide "evenly"- do we mean that the number should be divided in even factors? for example 9 (an odd) number can be divided by 3 bit there is no even factor. so, can we say that 3 divides 9 evenly? or only when a number has an even factor then we can say that number is "evenly" divided? Answer to this question will play a major role in solving above question.

Regards
Yash

Divide evenly simply means divides without a remainder, so we can say that 3 divides 9 evenly because 9/3 = 3, no remainder.
_________________
Re: Is x a prime number?   [#permalink] 01 Sep 2016, 02:25
Similar topics Replies Last post
Similar
Topics:
2 Is x a prime number? 2 25 May 2016, 14:31
12 Is x a prime number? 12 16 Feb 2015, 05:54
4 Is x a prime number? 8 16 Feb 2015, 05:47
5 If x is an integer, then is x a prime number? 5 04 May 2012, 19:51
16 Is root{x} a prime number? 23 26 Jan 2012, 05:41
Display posts from previous: Sort by