Find all School-related info fast with the new School-Specific MBA Forum

It is currently 19 Aug 2014, 21:01

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.

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

M03Q20

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
Intern
Intern
avatar
Joined: 06 May 2009
Posts: 12
Followers: 0

Kudos [?]: 0 [0], given: 3

Re: M03Q20 [#permalink] New post 28 May 2013, 09:18
Dixon wrote:
Just curious, would something like this be a 600-level question?


It was correctly answered by 83% of the people, I would say in the 500-600 range.
Intern
Intern
avatar
Joined: 08 May 2014
Posts: 2
Followers: 0

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

Re: M03Q20 [#permalink] New post 13 May 2014, 04:08
The answer is actually pretty easy. We are looking for an integer that divides 15! + 13, so (15! + 13) / q = n for some integers q and n. Using properties of fractions, this means (15!/q)+ (13/q) = n. Since 13 is prime, we know q must be 1 or 13. 1 is not an answer choice, so q must be 13. This can be checked further because by noting that 15!=15x14x13x12..., so we see 13 divides 15!, because 13 divides the third term of the factorial. Therefore 13 divides 15! and13, so 13 divides 15!+13 based on the above property of fractions.

The solution factoring out 13 is a better solution though.
Re: M03Q20   [#permalink] 13 May 2014, 04:08
Display posts from previous: Sort by

M03Q20

  Question banks Downloads My Bookmarks Reviews Important topics  

Go to page   Previous    1   2   [ 22 posts ] 

Moderators: Bunuel, WoundedTiger



cron

GMAT Club MBA Forum Home| About| Privacy Policy| Terms and Conditions| GMAT Club Rules| Contact| Sitemap

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®.