NEW HERE? LEARN MORE
closeclose
Last visit was: 23 Apr 2024, 12:39 It is currently 23 Apr 2024, 12:39
Decision Tracker
My Rewards
New posts
New comers' posts

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.
Go to My Error Log Learn more
Close
Request Expert Reply
Confirm Cancel

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

SORT BY:
Date
Kudos
Tags:
Find Similar Topics 
Show Tags
Hide Tags
User avatar
kashishh
Manager
Manager
Joined: 02 Jun 2011
Posts: 95
Own Kudos [?]: 376 [12]
Given Kudos: 11
Send PM
If x is a prime number, what is the value of x? [#permalink] New post   Updated on: 14 Dec 2018, 00:57
2
Kudos
10
Bookmarks
00:00
A
B
C
D
E

Difficulty:

65% (hard)

Question Stats:

42% (01:05) correct 58% (00:59) wrong based on 352 sessions
Hide Show timer Statistics
If x is a prime number, what is the value of x?

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


Show 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.
ShowHide Answer
Official Answer
E

Originally posted by kashishh on 27 Mar 2012, 14:07.
Last edited by Bunuel on 14 Dec 2018, 00:57, edited 2 times in total.
Edited.
Most Helpful Reply
User avatar
L
Bunuel
Math Expert
Joined: 02 Sep 2009
Posts: 92881
Own Kudos [?]: 618578 [10]
Given Kudos: 81562
Send PM
CAT Tests Forum Quiz Mode
If x is a prime number, what is the value of x? [#permalink] New post   27 Mar 2012, 14:15
4
Kudos
6
Bookmarks
Expert Reply
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, so it's a multiple of 5 too.

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

Answer: E.
General Discussion
User avatar
Senthil7
Senior Manager
Senior Manager
Joined: 31 Mar 2016
Posts: 325
Own Kudos [?]: 195 [0]
Given Kudos: 197
Location: India
Concentration: Operations, Finance
GMAT 1: 670 Q48 V34
GPA: 3.8
WE:Operations (Commercial Banking)
Send PM
GMAT ToolKit User
Re: If x is a prime number, what is the value of x? [#permalink] New post   16 Jun 2016, 10:45
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.
User avatar
G
TheMechanic
Manager
Manager
Joined: 19 Oct 2012
Posts: 222
Own Kudos [?]: 538 [1]
Given Kudos: 103
Location: India
Concentration: General Management, Operations
Schools: Anderson '16 Tepper '16 Kelley '16 Jones '16 (S) Carlson '16 ISB '18 (II) Duke '20 (S) McCombs '20 (II)
GMAT 1: 660 Q47 V35
GMAT 2: 710 Q50 V38
GPA: 3.81
WE:Information Technology (Computer Software)
Send PM
Re: If x is a prime number, what is the value of x? [#permalink] New post   21 Jul 2016, 11:36
1
Kudos
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.
User avatar
G
CounterSniper
Director
Director
Joined: 20 Feb 2015
Posts: 631
Own Kudos [?]: 711 [0]
Given Kudos: 74
Concentration: Strategy, General Management
Send PM
Re: If x is a prime number, what is the value of x? [#permalink] New post   23 Jul 2016, 06:50
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 :!:
avatar
B
sai897
Intern
Intern
Joined: 01 Aug 2016
Posts: 19
Own Kudos [?]: 4 [0]
Given Kudos: 74
Schools: ISB '18
Send PM
Re: If x is a prime number, what is the value of x? [#permalink] New post   02 Jan 2017, 21:00
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
User avatar
D
stonecold
Alum
Joined: 12 Aug 2015
Posts: 2282
Own Kudos [?]: 3124 [0]
Given Kudos: 893
Schools: Boston U '20 (M)
GRE 1: Q169 V154
Send PM
GMAT ToolKit User
Re: If x is a prime number, what is the value of x? [#permalink] New post   14 Jan 2017, 04:10
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.
User avatar
B
srinidhi mishra
Intern
Intern
Joined: 01 May 2017
Posts: 11
Own Kudos [?]: 1 [0]
Given Kudos: 8
Concentration: General Management, Leadership
Send PM
Re: If x is a prime number, what is the value of x? [#permalink] New post   07 Jun 2017, 11:34
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.

1-x<15 i.e. x=3,5,7,11,13
2-x-2=5n i.e. x=7,17,37,47 etc

7 is common hence C

x=0 is not the case since 0 is not a prime number ?
avatar
B
Ibrahim13
Intern
Intern
Joined: 27 Nov 2020
Posts: 9
Own Kudos [?]: 0 [0]
Given Kudos: 9
Send PM
Re: If x is a prime number, what is the value of x? [#permalink] New post   04 Feb 2021, 15:14
(×-2) is multiple of 5. Can someone please explain. Thank you

Posted from my mobile device
GMAT Club Bot
gmatclubot
Re: If x is a prime number, what is the value of x? [#permalink]
04 Feb 2021, 15:14
Moderator:
Bunuel
Math Expert
92881 posts

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne
Main navigation
GMAT Resources
Partners
MBA Resources
www.gmac.com|www.mba.com | | GMAT Club Rules | Terms and Conditions