Check GMAT Club Decision Tracker for the Latest School Decision Releases https://gmatclub.com/AppTrack

 It is currently 25 May 2017, 15:31

### 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

# Factorials

 post reply Question banks Downloads My Bookmarks Reviews Important topics
Author Message
Intern
Joined: 23 May 2008
Posts: 48
Followers: 0

Kudos [?]: 79 [0], given: 0

### Show Tags

08 Oct 2008, 11:42
This topic is locked. If you want to discuss this question please re-post it in the respective forum.

On pg 338 of the OG, question 153, explanation B it tries to explain the following:

"...2 is a factor of 13! + 2, since it is a factor of both 13! and 2..."

How do we know that 2 is a factor of 13!?
Manager
Joined: 27 Sep 2008
Posts: 76
Followers: 1

Kudos [?]: 8 [0], given: 0

### Show Tags

08 Oct 2008, 12:21
easy !!

13!/2 = (1*2*3*4*5*6*7... 13)/2

so 13!/2 = integer

Intern
Joined: 23 May 2008
Posts: 48
Followers: 0

Kudos [?]: 79 [0], given: 0

### Show Tags

08 Oct 2008, 12:35
Sorry, still not getting it. I understand how to get to the factorial of 13! (1*2*3*4*5*6*7... 13). How is it common knowledge though that 2 is a factor of 13! without doing all the math?
Manager
Joined: 27 Sep 2008
Posts: 76
Followers: 1

Kudos [?]: 8 [0], given: 0

### Show Tags

08 Oct 2008, 12:39
snowbirdskier wrote:
Sorry, still not getting it. I understand how to get to the factorial of 13! (1*2*3*4*5*6*7... 13). How is it common knowledge though that 2 is a factor of 13! without doing all the math?

You will agree that 2&3 are factors of 6 since 6 can be written as 2*3 = 6 , same way 13!

Intern
Joined: 23 May 2008
Posts: 48
Followers: 0

Kudos [?]: 79 [0], given: 0

### Show Tags

08 Oct 2008, 12:44
Okay, you're right. That is easy. Thanks.
Re: Factorials   [#permalink] 08 Oct 2008, 12:44
Display posts from previous: Sort by

# Factorials

 post reply Question banks Downloads My Bookmarks Reviews Important topics

 Powered by phpBB © phpBB Group and phpBB SEO 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®.