If m is a positive odd integer between 2 and 30, then m is

Oldest

Best Reply

Author

Message

TAGS:

Manager

Joined: 02 Jun 2011

Posts: 160

Followers: 1

Kudos [?]: 4 [0], given: 11

If m is a positive odd integer between 2 and 30, then m is [#permalink]

26 Apr 2012, 02:54

00:00

Question Stats:

58% (01:00) correct

41% (01:33) wrong

based on 0 sessions

If m is a positive odd integer between 2 and 30, then m is divisible by how many different positive prime numbers?

(1) m is not divisible by 3.
(2) m is not divisible by 5.

OA is A
My doubt is when we analyse stat. 1, aren’t we left with
7,11,13,17,19,23,25,29
out of which isn’t 25 has a different answer to the question than the other numbers?
don’t we need stat. 2 to answer it?

[Reveal] Spoiler: OA

GMAT Club team member

Joined: 02 Sep 2009

Posts: 11628

Followers: 1802

Kudos [?]: 9614 [1] , given: 829

Re: divisibility problem [#permalink]

26 Apr 2012, 03:08

This post received
KUDOS

kashishh wrote:

No, since 25 (as well as all other possible values of m from statement (1)), is divisible only by one prime number - 5.

If m is a positive odd integer between 2 and 30, then m is divisible by how many different positive prime numbers?

Since the range is not that big we can write down all possible value of m for each statement.

(1) m is not divisible by 3 --> m can be: 5, 7, 11, 13, 17, 19, 23, 25, and 29. Each has only one distinct prime in its prime factorization. Sufficient.

(2) m is not divisible by 5 --> m can be: 3, 7, 9, 11, 13, 17, 19, 21, STOP. Each but 21 has one prime in its prime factorization, while 21 has two primes: 3 and 7. Not sufficient.

Answer: A.

Hope it's clear.
_________________

PLEASE READ AND FOLLOW: 11 Rules for Posting!!!

RESOURCES: [GMAT MATH BOOK]; 1. Triangles; 2. Polygons; 3. Coordinate Geometry; 4. Factorials; 5. Circles; 6. Number Theory

COLLECTION OF QUESTIONS:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. NEW!!!

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS ; 9 Devil's Dozen!!!; 10 Number Properties set. NEW!!!

What are GMAT Club Tests?
25 extra-hard Quant Tests

Find out what's new at GMAT Club - latest features and updates

Veritas Prep GMAT Instructor

Joined: 16 Oct 2010

Posts: 3114

Location: Pune, India

Followers: 573

Kudos [?]: 2021 [1] , given: 92

Re: If m is a positive odd integer between 2 and 30, then m is [#permalink]

26 Apr 2012, 04:26

This post received
KUDOS

kashishh wrote:

The question asks for "... how many different prime numbers?"
If you are thinking that 25 is divisible by 5 and 5, it still counts as one.

(1) m is not divisible by 3
m is not divisible by 2 anyway since we are talking about odd numbers. Next prime number is 5. The next one is 7 but 5*7 = 35 which is greater than 30. So even if we take the two smallest possible primes, no odd number in the given range can have both as factors. So m must have only one prime number as a factor.

(2) m is not divisible by 5
m could be divisible by 3 and 7 (since 3*7 = 21 which lies in our range). So m could be divisible by one prime or by two different primes. So this statement is not sufficient.

Answer (A)
_________________

Karishma
Veritas Prep | GMAT Instructor
My Blog

Save 10% on Veritas Prep GMAT Courses And Admissions Consulting
Enroll now. Pay later. Take advantage of Veritas Prep's flexible payment plan options.

Veritas Prep Reviews

SVP

Joined: 01 Sep 2010

Posts: 1747

Followers: 56

Kudos [?]: 585 [0], given: 467

If m is a positive odd integer between 2 and 30, then how [#permalink]

04 Oct 2012, 15:09

If m is a positive odd integer between 2 and 30, then how many different positive prime numbers is m divisible by?

(1) m is not divisible by 3

(2) m is not divisible by 5
_________________

KUDOS is the good manner to help the entire community.

GMAT Club team member

Joined: 02 Sep 2009

Posts: 11628

Followers: 1802

Kudos [?]: 9614 [0], given: 829

Re: If m is a positive odd integer between 2 and 30, then how [#permalink]

04 Oct 2012, 15:17

carcass wrote:

If m is a positive odd integer between 2 and 30, then how many different positive prime numbers is m divisible by?

(1) m is not divisible by 3

(2) m is not divisible by 5

Merging similar topics. Please refer to the solutions above.
_________________

Re: If m is a positive odd integer between 2 and 30, then how [#permalink] 04 Oct 2012, 15:17

	Similar topics	Author	Replies	Last post
Similar Topics:	If m is a positive odd integer between 2 and 30, then m is	nickdawg	1	27 Nov 2005, 00:52
	If M is a positive odd integer between 2 and 30, then M is	khushi1	2	07 Dec 2007, 04:17
	If m is a positive odd integer between 2 and 30, then m is	shils01	1	31 Mar 2008, 08:49
	If m is a positive odd integer between 2 and 30, then m is	sondenso	7	23 Jul 2008, 20:37
	If m is a positive odd integer between 2 and 30, then m is	ugimba	5	26 Apr 2009, 16:10

If m is a positive odd integer between 2 and 30, then m is

Main navigation

GMAT Resources

Partners

MBA Resources

GMAT ® is a registered trademark of the Graduate Management Admission Council ® (GMAC ®). GMAT Club's website has not been reviewed or endorsed by GMAC.