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

It is currently 02 Oct 2014, 02:31

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

Can teh positive integer n be written as the sum of two

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
Manager
Manager
avatar
Joined: 23 Mar 2008
Posts: 226
Followers: 1

Kudos [?]: 13 [0], given: 0

Can teh positive integer n be written as the sum of two [#permalink] New post 31 Mar 2008, 10:08
Can teh positive integer n be written as the sum of two different positive prime numbers?

1) n is greater than 3
2) n is odd

many thanks
Intern
Intern
avatar
Joined: 31 Mar 2008
Posts: 14
Followers: 0

Kudos [?]: 1 [0], given: 0

Re: positive integer [#permalink] New post 31 Mar 2008, 10:14
primes: 1,3,5,7,11,13,17,etc

sum of any two primes is even.

answer = no
Senior Manager
Senior Manager
User avatar
Joined: 20 Dec 2004
Posts: 258
Followers: 6

Kudos [?]: 68 [0], given: 0

Re: positive integer [#permalink] New post 02 Apr 2008, 07:33
onyxls1 wrote:

sum of any two primes is even.



5 = 2 + 3 (2 & 3 are prime but 5 is not even)
7 = 2 + 5 (2 & 5 are prime but 7 is not even)
9 = 2 + 7 (2 & 7 are prime but 9 is not even)
13 = 2 + 11 (2 & 11 are prime but 13 is not even)
_________________

Stay Hungry, Stay Foolish

Current Student
avatar
Joined: 28 Dec 2004
Posts: 3404
Location: New York City
Schools: Wharton'11 HBS'12
Followers: 13

Kudos [?]: 162 [0], given: 2

Re: positive integer [#permalink] New post 02 Apr 2008, 07:37
I will go with E..

pick 23..23 cannot be expressed as the sum of 2 different primes

13 can be expressed as 11+2
Expert Post
CEO
CEO
User avatar
Joined: 17 Nov 2007
Posts: 3571
Concentration: Entrepreneurship, Other
Schools: Chicago (Booth) - Class of 2011
GMAT 1: 750 Q50 V40
Followers: 365

Kudos [?]: 1809 [0], given: 358

GMAT ToolKit User Premium Member
Re: positive integer [#permalink] New post 02 Apr 2008, 07:45
Expert's post
E

1. Let n satisfies both conditions
2. n can be odd only if one of the prime numbers is 2.
3. Therefore, n=p+2
4. p can be prime number (5,7,11,13,17) and can be not prime number (9,15)
5. Therefore, E

we now can also construct two examples:
5=3+2 and 11=9+2
_________________

HOT! GMAT TOOLKIT 2 (iOS) / GMAT TOOLKIT (Android) - The OFFICIAL GMAT CLUB PREP APP, a must-have app especially if you aim at 700+ | PrepGame

CEO
CEO
User avatar
Joined: 29 Mar 2007
Posts: 2593
Followers: 16

Kudos [?]: 193 [0], given: 0

Re: positive integer [#permalink] New post 02 Apr 2008, 07:54
puma wrote:
Can teh positive integer n be written as the sum of two different positive prime numbers?

1) n is greater than 3
2) n is odd

many thanks


E.

Personally I don't like the wording of this DS question. It can be confusing.

The question is asking can it be the sum of two positve prime numbers. Well really we can answer Yes it can be. It should read "IS n the sum of two different positive prime numbers." Just my opionion there.

Anyway when you get these, follow the same rules that apply to all yes and no questions.
Re: positive integer   [#permalink] 02 Apr 2008, 07:54
    Similar topics Author Replies Last post
Similar
Topics:
7 Experts publish their posts in the topic Can the positive integer n be written as the sum of two diff Bunuel 9 12 Feb 2014, 01:14
Can the positive integer n be written as the sum of two... Stiv 0 12 Aug 2013, 02:24
1 Experts publish their posts in the topic Can the positive integer n be written as the sum of two monikaleoster 8 29 Jan 2012, 10:56
Can the positive integer n be written as the sum of two aaron22197 10 17 Jun 2008, 07:14
Can the positive integer n be written as the sum of two amansingla4 4 15 May 2006, 01:20
Display posts from previous: Sort by

Can teh positive integer n be written as the sum of two

  Question banks Downloads My Bookmarks Reviews Important topics  


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®.