If x is a prime number, what is the value of x? : GMAT Data Sufficiency (DS)
Check GMAT Club Decision Tracker for the Latest School Decision Releases http://gmatclub.com/AppTrack

 It is currently 22 Jan 2017, 05:01

### 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

# If x is a prime number, what is the value of x?

Author Message
TAGS:

### Hide Tags

Manager
Joined: 02 Jun 2011
Posts: 159
Followers: 1

Kudos [?]: 75 [0], given: 11

If x is a prime number, what is the value of x? [#permalink]

### Show Tags

27 Mar 2012, 13:07
2
This post was
BOOKMARKED
00:00

Difficulty:

65% (hard)

Question Stats:

44% (01:47) correct 56% (00:40) wrong based on 194 sessions

### HideShow timer Statistics

If x is a prime number, what is the value of x?

(1) x is less than 15
(2) (x-2) is multiple of 5.

[Reveal] Spoiler:
first thing x is prime given in question.
st. 1.) gives the options 2,3,5,7,11,13 so not sufficient
st. 2.) for x-2 to be a multiple of 5 x could be 7, 17 etc as the question says x to be prime
but st 2. not suffiecient

together isnt the only option is 7 ?
as st. 1. says less than 15 and st. 2 states x-2 is multiple of 5
shouldn't the answer be c? given as E.
[Reveal] Spoiler: OA

Last edited by stonecold on 02 Jan 2017, 16:30, edited 1 time in total.
Edited.
Math Expert
Joined: 02 Sep 2009
Posts: 36596
Followers: 7093

Kudos [?]: 93422 [1] , given: 10563

Re: If x is a prime number, what is the value of x? [#permalink]

### Show Tags

27 Mar 2012, 13:15
1
KUDOS
Expert's post
7
This post was
BOOKMARKED
kashishh wrote:
If x is a prime number, what is the value of x?

(1) x is less than 15
(2) (x-2) is multiple of 5.

first thing x is prime given in question.
st. 1.) gives the options 2,3,5,7,11,13 so not sufficient
st. 2.) for x-2 to be a multiple of 5 x could be 7, 17 etc as the question says x to be prime
but st 2. not suffiecient

together isnt the only option is 7 ?
as st. 1. says less than 15 and st. 2 states x-2 is multiple of 5
shouldn't the answer be c? given as E.

If x is a prime number, what is the value of x?

(1) x is less than 15 --> x can be 2, 3, 5, 7, 11, or 13. Not sufficient.
(2) (x-2) is multiple of 5 --> also not sufficient, since x can take more than 1 value, for example 2, 7, 17, ... Not sufficient.

Notice that 2 is a possible value for x, since 2-2=0 and zero is a multiple of every integer (except zero itself), so it's a multiple of 5 too.

(1)+(2) x can still be 2 or 7. Not sufficient.

_________________
GMAT Club Legend
Joined: 09 Sep 2013
Posts: 13497
Followers: 577

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

Re: If x is a prime number, what is the value of x? [#permalink]

### Show Tags

05 Sep 2014, 04:38
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.
_________________
Senior Manager
Joined: 31 Mar 2016
Posts: 415
Location: India
Concentration: Operations, Finance
GMAT 1: 670 Q48 V34
GPA: 3.8
WE: Operations (Commercial Banking)
Followers: 14

Kudos [?]: 53 [0], given: 197

Re: If x is a prime number, what is the value of x? [#permalink]

### Show Tags

16 Jun 2016, 09:45
If x is a prime number, what is the value of x?

(1) x is less than 15
(2) (x-2) is multiple of 5.
.
A prime number is a whole number greater than 1, whose only two whole-number factors are 1 and itself. If this is the constraint then considering statement 2 it means x-2 is multiple of 5 or in other words x-2 is divisible by 5. Therefore the only values possible to satisfy the constraint of being a prime number and x-2 being divisible by 5 are:

7 and 17 => x-2 is 5 and x-2 is 15 both divisible by 5. Take 1 and 2 together x<15 , x is prime and x-2 divisible by 5 only integer value possible is 7. Hence I think correct answer is C. I disagree with above explanation by Bunuel as 0 is not prime as given in question constraint.
Manager
Joined: 19 Oct 2012
Posts: 222
Location: India
Concentration: General Management, Operations
GMAT 1: 660 Q47 V35
GPA: 3.81
WE: Information Technology (Computer Software)
Followers: 1

Kudos [?]: 9 [0], given: 32

Re: If x is a prime number, what is the value of x? [#permalink]

### Show Tags

21 Jul 2016, 10:36
Here is my retake and I hope it clears the air:

we know stmt 1 doesnt suffice. So, A and D are out.
Stmt 2 gives us: (x-2) is a multiple of 5. This can we written as (x-2)= 5 x k(natural number)
or x= 5k+2. now the possible values of k could be (keeping in mind X is a prime number).
if k=0, then x=2
if k=1, then x=7
if k=3, then x=17 and so on.
Clearly stmnt 2 is not sufficient in itself.
Combining Stmt1 and Stmt2, we get x is less than 15 and therefore, x can have 2 and 7 as valid values. Since we have to find a unique value of x, both the stmts are not sufficient.

There fore, E.
_________________

Citius, Altius, Fortius

Senior Manager
Joined: 20 Feb 2015
Posts: 389
Concentration: Strategy, General Management
Followers: 2

Kudos [?]: 63 [0], given: 10

Re: If x is a prime number, what is the value of x? [#permalink]

### Show Tags

23 Jul 2016, 05:50
Senthil7 wrote:
If x is a prime number, what is the value of x?

(1) x is less than 15
(2) (x-2) is multiple of 5.
.
A prime number is a whole number greater than 1, whose only two whole-number factors are 1 and itself. If this is the constraint then considering statement 2 it means x-2 is multiple of 5 or in other words x-2 is divisible by 5. Therefore the only values possible to satisfy the constraint of being a prime number and x-2 being divisible by 5 are:

7 and 17 => x-2 is 5 and x-2 is 15 both divisible by 5. Take 1 and 2 together x<15 , x is prime and x-2 divisible by 5 only integer value possible is 7. Hence I think correct answer is C. I disagree with above explanation by Bunuel as 0 is not prime as given in question constraint.

he took x=2,which is a prime and not x=0
Intern
Joined: 01 Aug 2016
Posts: 19
Schools: ISB '17
Followers: 0

Kudos [?]: 0 [0], given: 53

Re: If x is a prime number, what is the value of x? [#permalink]

### Show Tags

02 Jan 2017, 20:00
In first option we have x=2,3,5,7 ----- so not possible

In second option we have

if x=2 then x-2 = 2-2= 0 is a multiple of 5.

Same as x=7,17--- will follow. So not possible..

If we combine 2 statements then x=2,7. Not sufficient. Answer is E
BSchool Forum Moderator
Joined: 12 Aug 2015
Posts: 1901
Followers: 49

Kudos [?]: 369 [0], given: 454

Re: If x is a prime number, what is the value of x? [#permalink]

### Show Tags

14 Jan 2017, 03:10
x is a prime number.
We need to get x

statement 1 => x<15 => x can be => {2,3,5,7,11,13} => insuff
statement 2 => x=5k+2 => x can be 2 or 7 => insuff
combining the two statements => x can be 2 or 7 .
No exact values=> clearly insuff

Hence E.

_________________

Mock Test -1 (Integer Properties Basic Quiz) ---> http://gmatclub.com/forum/stonecold-s-mock-test-217160.html#p1676182

Mock Test -2 (Integer Properties Advanced Quiz) --->http://gmatclub.com/forum/stonecold-s-mock-test-217160.html#p1765951

Mock Test -2 (Evensand Odds Basic Quiz) --->http://gmatclub.com/forum/stonecold-s-mock-test-217160.html#p1768023

Give me a hell yeah ...!!!!!

Re: If x is a prime number, what is the value of x?   [#permalink] 14 Jan 2017, 03:10
Similar topics Replies Last post
Similar
Topics:
If x is a prime number, what is the value of x. 2 28 Oct 2016, 02:52
3 If x is a prime number, what is the value of x. 4 28 Oct 2016, 02:50
If x is a prime number, what is the value of x? 14 25 Jun 2011, 03:58
12 If x and y are prime numbers, what is the value of |x-y|? 12 15 Mar 2011, 15:36
31 If x is a prime number, what is the value of x? 14 23 Dec 2009, 09:16
Display posts from previous: Sort by