Last visit was: 23 Apr 2026, 15:09 It is currently 23 Apr 2026, 15:09
Home
Messages
Tests
Schools
Events
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
Back to Forum
Create Topic
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 23 Apr 2026
Posts: 109,785
Own Kudos:
810,859
 [2]
Given Kudos: 105,853
Products:
GMAT Club Tests Forum Quiz
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 109,785
Kudos: 810,859
 [2]
Is integer x prime? (1) x = | x | (2) x! = | x | 10 Dec 2016, 06:33
Kudos
Add Kudos
2
Bookmarks
Bookmark this Post
00:00
Start Timer
Pause Timer
Resume Timer
Show Answer
Hide
Show
History
E
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!

Difficulty:

35% (medium)

Question Stats:

64% (01:01) correct 36% (00:59) wrong based on 281 sessions

History

Date
Time
Result
Not Attempted Yet
Is integer x prime?

(1) x = | x |
(2) x! = | x |
ShowHide Answer
Official Answer
E
User avatar
prashantrchawla
User avatar
Joined: 02 Nov 2013
Last visit: 10 Feb 2017
Posts: 58
Own Kudos:
31
 [1]
Given Kudos: 10
Location: India
Posts: 58
Kudos: 31
 [1]
Is integer x prime? (1) x = | x | (2) x! = | x | 10 Dec 2016, 09:06
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
We need to find out whether x is prime or not ?
Option 1: x = | x |, All the positive values will satisfy this equation. Not sufficient.
Option 2: x! = | x |, For two values of x, i.e. 1 and 2 will satisfy this equation. Not sufficient
Taking both the options, will not satisfy this options. Hence answer is E. Hope I am right ?
User avatar
AR15J
User avatar
Joined: 21 Aug 2016
Last visit: 15 May 2024
Posts: 210
Own Kudos:
163
Given Kudos: 145
Location: India
GPA: 3.9
WE:Information Technology (Computer Software)
Products:
My Reviews
Posts: 210
Kudos: 163
Is integer x prime? (1) x = | x | (2) x! = | x | 10 Dec 2016, 09:37
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Statement 1: x can be equal to |x| only for non-negative integers, but it does tell if x is prime or not

Statement 2: x!=|x|

Above condition is true for x=1,2

1 is not a prime number while 2 is a prime number => statement 2 is not sufficient

Combining both:

both conditions are satisfied when x=1,2 (same as statement 2)

So E is the correct answer

+1 Kudos if you like the post :)
avatar
shikha.lakhani
avatar
Joined: 08 Jan 2015
Last visit: 26 May 2018
Posts: 5
Own Kudos:
8
Given Kudos: 127
Location: India
Concentration: Strategy, Operations
Schools: Tepper '20 Rotman '20 Anderson '20 Duke Fuqua Duke '20 McCombs '20 Goizueta '20 Kelley '20 Simon '20
GMAT 1: 650 Q48 V41
GMAT 2: 720 Q48 V41
GPA: 2.8
WE:Analyst (Internet and New Media)
Products:
My Reviews
Schools: Tepper '20 Rotman '20 Anderson '20 Duke Fuqua Duke '20 McCombs '20 Goizueta '20 Kelley '20 Simon '20
GMAT 2: 720 Q48 V41
Posts: 5
Kudos: 8
Is integer x prime? (1) x = | x | (2) x! = | x | 23 Feb 2017, 05:13
Kudos
Add Kudos
Bookmarks
Bookmark this Post
what does x! mean? did not get the b condition
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 23 Apr 2026
Posts: 109,785
Own Kudos:
810,859
 [1]
Given Kudos: 105,853
Products:
GMAT Club Tests Forum Quiz
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 109,785
Kudos: 810,859
 [1]
Is integer x prime? (1) x = | x | (2) x! = | x | 23 Feb 2017, 05:49
Kudos
Add Kudos
1
Bookmarks
Bookmark this Post
shikha.lakhani
what does x! mean? did not get the b condition
Show more

Definition

The factorial of a non-negative integer \(n\), denoted by \(n!\), is the product of all positive integers less than or equal to \(n\).

For example: \(4!=1*2*3*4=24\).

Properties

  • Factorial of a negative number is undefined.
  • \(0!=1\), zero factorial is defined to equal 1.
  • \(n!=(n-1)!*n\), valid for \(n\geq{1}\).
User avatar
KrishnakumarKA1
User avatar
Joined: 05 Jan 2017
Last visit: 13 Oct 2020
Posts: 398
Own Kudos:
314
 [1]
Given Kudos: 15
Location: India
Posts: 398
Kudos: 314
 [1]
Is integer x prime? (1) x = | x | (2) x! = | x | 23 Feb 2017, 06:58
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Is integer x prime?

(1) x = | x |
(2) x! = | x |

Prompt analysis
x is an integer

Super set
the answer will be either yes or no

Translation

In order to find the answer, we need:
1# exact value of x
2# any equation to find the value of x
3# any property to narrow down the value to 1

statement analysis
St 1: x = |x|. this will hold for any positive value of x. INSUFFICIENT
St 2: x! = |x|. this will hold for x = 1 and 2. INSUFFICIENT
St1 & St2: again both the condition is true for x = 1 and 2. INSUFFICIENT

Option E
Moderators:
Bunuel
Math Expert
109785 posts
kingbucky
498 posts
Gmat860sanskar
212 posts