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

It is currently 29 Jun 2016, 22:29
GMAT Club Tests

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

How many of the factors of 72 are divisible by 2? 4 5 6

  post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
CEO
CEO
User avatar
Joined: 21 Jan 2007
Posts: 2756
Location: New York City
Followers: 9

Kudos [?]: 649 [0], given: 4

How many of the factors of 72 are divisible by 2? 4 5 6 [#permalink]

Show Tags

New post 21 Nov 2007, 08:07
00:00
A
B
C
D
E

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 0 sessions

HideShow timer Statistics

This topic is locked. If you want to discuss this question please re-post it in the respective forum.

How many of the factors of 72 are divisible by 2?

4
5
6
8
9

Is there a shortcut to this question? It is rather tedious to list out all factors of 72
Expert Post
CEO
CEO
User avatar
Joined: 17 Nov 2007
Posts: 3580
Concentration: Entrepreneurship, Other
Schools: Chicago (Booth) - Class of 2011
GMAT 1: 750 Q50 V40
Followers: 485

Kudos [?]: 2802 [0], given: 359

GMAT ToolKit User Premium Member
 [#permalink]

Show Tags

New post 21 Nov 2007, 08:32
Expert's post
E.

72=2^3*3^2

N0=(3+1)(2+1)=12 - numbers of all factors

N1=(2+1)=3 - numbers of all factors that are not divisible by 2

Therefore, 12-3=9

9.
CEO
CEO
User avatar
Joined: 21 Jan 2007
Posts: 2756
Location: New York City
Followers: 9

Kudos [?]: 649 [0], given: 4

 [#permalink]

Show Tags

New post 23 Nov 2007, 13:28
bmwhype2 wrote:
walker wrote:
E.

72=2^3*3^2

N0=(3+1)(2+1)=12 - numbers of all factors

N1=(2+1)=3 - numbers of all factors that are not divisible by 2

Therefore, 12-3=9

9.


Can you explain the logic of that?


lets say we have some random number N and its factors are
2^4 * 5^2 *7^2

The number of factors that are not divisible by 2 are 3*3=9?
Senior Manager
Senior Manager
User avatar
Joined: 09 Oct 2007
Posts: 466
Followers: 1

Kudos [?]: 33 [0], given: 1

 [#permalink]

Show Tags

New post 24 Nov 2007, 10:34
bmwhype2 wrote:
bmwhype2 wrote:
walker wrote:
E.

72=2^3*3^2

N0=(3+1)(2+1)=12 - numbers of all factors

N1=(2+1)=3 - numbers of all factors that are not divisible by 2

Therefore, 12-3=9

9.


Can you explain the logic of that?


lets say we have some random number N and its factors are
2^4 * 5^2 *7^2

The number of factors that are not divisible by 2 are 3*3=9?


Any answers on this? Thought I should keep this alive (:
Intern
Intern
avatar
Joined: 04 Sep 2007
Posts: 12
Followers: 0

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

 [#permalink]

Show Tags

New post 25 Nov 2007, 03:23
bmwhype2 wrote:
bmwhype2 wrote:
walker wrote:
E.

72=2^3*3^2

N0=(3+1)(2+1)=12 - numbers of all factors

N1=(2+1)=3 - numbers of all factors that are not divisible by 2

Therefore, 12-3=9

9.


Can you explain the logic of that?


lets say we have some random number N and its factors are
2^4 * 5^2 *7^2

The number of factors that are not divisible by 2 are 3*3=9?


I think so.
1
5
7
5*5
7*7
5*7
5*5*7
7*7*5
5*5*7*7

If this is proven to be a general rule, is very very useful.
CEO
CEO
User avatar
Joined: 21 Jan 2007
Posts: 2756
Location: New York City
Followers: 9

Kudos [?]: 649 [0], given: 4

 [#permalink]

Show Tags

New post 28 Nov 2007, 05:40
bmwhype2 wrote:
bmwhype2 wrote:
walker wrote:
E.

72=2^3*3^2

N0=(3+1)(2+1)=12 - numbers of all factors

N1=(2+1)=3 - numbers of all factors that are not divisible by 2

Therefore, 12-3=9

9.


Can you explain the logic of that?


lets say we have some random number N and its factors are
2^4 * 5^2 *7^2

The number of factors that are not divisible by 2 are 3*3=9?


think i made a mistake.

its 5*3*3 = 45 total factors
45 - (3 + 3) = 26
  [#permalink] 28 Nov 2007, 05:40
Display posts from previous: Sort by

How many of the factors of 72 are divisible by 2? 4 5 6

  post reply Question banks Downloads My Bookmarks Reviews Important topics  


GMAT Club MBA Forum Home| About| 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®.