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

 It is currently 29 Apr 2016, 13:21

### 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

# Is 30 a factor of n?

 Question banks Downloads My Bookmarks Reviews Important topics
Author Message
TAGS:

### Hide Tags

Current Student
Status: Never ever give up on yourself.Period.
Joined: 23 Aug 2012
Posts: 152
Location: India
Concentration: Finance, Human Resources
GMAT 1: 570 Q47 V21
GMAT 2: 690 Q50 V33
GPA: 3.5
WE: Information Technology (Investment Banking)
Followers: 9

Kudos [?]: 234 [0], given: 35

Is 30 a factor of n? [#permalink]

### Show Tags

04 Jan 2013, 07:33
3
This post was
BOOKMARKED
00:00

Difficulty:

75% (hard)

Question Stats:

28% (01:46) correct 72% (01:01) wrong based on 81 sessions

### HideShow timer Statictics

Is 30 a factor of n?

(1) 30 is a factor of the square of n
(2) 30 is a factor of 2n

I doubt on OA...plz clarify
[Reveal] Spoiler: OA

_________________

Don't give up on yourself ever. Period.
Beat it, no one wants to be defeated (My journey from 570 to 690) : beat-it-no-one-wants-to-be-defeated-journey-570-to-149968.html

Math Expert
Joined: 02 Sep 2009
Posts: 32531
Followers: 5624

Kudos [?]: 68230 [4] , given: 9797

Re: Is 30 a factor of n? [#permalink]

### Show Tags

04 Jan 2013, 07:45
4
KUDOS
Expert's post
2
This post was
BOOKMARKED
daviesj wrote:
Is 30 a factor of n?

(1) 30 is a factor of the square of n
(2) 30 is a factor of 2n

I doubt on OA...plz clarify

Every GMAT divisibility question will tell you in advance that any unknowns represent positive integers, which means that ALL GMAT divisibility questions are limited to positive integers only.

If n is not an integer, then the question does not make sense (at least for GMAT) .

The question should read:
If n is an integer, is 30 a factor of n?

(1) 30 is a factor of n^2. If 30=2*3*5 is not a factor of n (if 2, 3 and 5 are not factors of n), then how this factors could appear in n^2? Exponentiation doesn't "produce" primes. Sufficient.

(2) 30 is a factor of 2n. Clearly insufficient: if n=15 then the answer is NO but if n=30 then the answer is YES. Not sufficient.

_________________
Math Expert
Joined: 02 Sep 2009
Posts: 32531
Followers: 5624

Kudos [?]: 68230 [1] , given: 9797

Re: Is 30 a factor of n? [#permalink]

### Show Tags

04 Jan 2013, 08:01
1
KUDOS
Expert's post
MacFauz wrote:
Bunuel wrote:
daviesj wrote:
Is 30 a factor of n?

(1) 30 is a factor of the square of n
(2) 30 is a factor of 2n

I doubt on OA...plz clarify

Every GMAT divisibility question will tell you in advance that any unknowns represent positive integers, which means that ALL GMAT divisibility questions are limited to positive integers only.

If n is not an integer, then the question does not make sense (at least for GMAT) .

The question should read:
If n is an integer, is 30 a factor of n?

(1) 30 is a factor of n^2. If 30=2*3*5 is not a factor of n (if 2, 3 and 5 are not factors of n), then how this factors could appear in n^2? Exponentiation doesn't "produce" primes. Sufficient.

(2) 30 is a factor of 2n. Clearly insufficient: if n=15 then the answer is NO but if n=30 then the answer is YES. Not sufficient.

Hi Bunuel,

Just curious.. Why would the question not make sense if "n" were not an integer?

It does not make sense for GMAT since only integers can have factors.
_________________
Math Expert
Joined: 02 Sep 2009
Posts: 32531
Followers: 5624

Kudos [?]: 68230 [1] , given: 9797

Re: Is 30 a factor of n? [#permalink]

### Show Tags

23 Mar 2016, 11:43
1
KUDOS
Expert's post
sameerspice wrote:
Bunuel wrote:
daviesj wrote:
Is 30 a factor of n?

(1) 30 is a factor of the square of n
(2) 30 is a factor of 2n

I doubt on OA...plz clarify

Every GMAT divisibility question will tell you in advance that any unknowns represent positive integers, which means that ALL GMAT divisibility questions are limited to positive integers only.

If n is not an integer, then the question does not make sense (at least for GMAT) .

The question should read:
If n is an integer, is 30 a factor of n?

(1) 30 is a factor of n^2. If 30=2*3*5 is not a factor of n (if 2, 3 and 5 are not factors of n), then how this factors could appear in n^2? Exponentiation doesn't "produce" primes. Sufficient.

(2) 30 is a factor of 2n. Clearly insufficient: if n=15 then the answer is NO but if n=30 then the answer is YES. Not sufficient.

Hello Bunuel,
Is there a reference for your statement
Every GMAT divisibility question will tell you in advance that any unknowns represent positive integers, which means that ALL GMAT divisibility questions are limited to positive integers only.

somewhere in GMAT official guide. I am little confused here, because almost in every DS question we are told to not assume a number as +ve or as integer unless otherwise advised.

In my opinion, given in this question we must not assume that "n" is positive integer.

I'm not saying that one should assume this. I'm saying that in its current form the question is NOT GMAT like because every GMAT divisibility question will tell you in advance that any unknowns represent positive integers. So, if it were proper GMAT question we would be given that n is an integer.
_________________
Moderator
Joined: 02 Jul 2012
Posts: 1230
Location: India
Concentration: Strategy
GMAT 1: 740 Q49 V42
GPA: 3.8
WE: Engineering (Energy and Utilities)
Followers: 105

Kudos [?]: 1135 [0], given: 116

Re: Is 30 a factor of n? [#permalink]

### Show Tags

04 Jan 2013, 07:43
daviesj wrote:
is 30 a factor of n?
(1) 30 is a factor of the square of n
(2) 30 is a factor of 2n

I doubt on OA...plz clarify

1) If n is $$\sqrt{30}$$, Answer is no. If n is 30, answer is yes. Insufficient.

2)If n = 15, answer is no. If n = 30, answer is yes. Insufficient.

1 & 2 together. 2n has to be an even number to be divisible by 30. Hence, n has to be an integer. $$n^2$$ is divisible by 30. So $$n^2$$ should have at least one 2, one 3 and one 5. Since $$n^2$$ is the square of an integer, this further implies that n^2 has to have at least two 2s, two 3s and two 5s. Hence n has at least one 2, one 3 and one 5. Hence divisible.

_________________

Did you find this post helpful?... Please let me know through the Kudos button.

Thanks To The Almighty - My GMAT Debrief

GMAT Reading Comprehension: 7 Most Common Passage Types

Moderator
Joined: 02 Jul 2012
Posts: 1230
Location: India
Concentration: Strategy
GMAT 1: 740 Q49 V42
GPA: 3.8
WE: Engineering (Energy and Utilities)
Followers: 105

Kudos [?]: 1135 [0], given: 116

Re: Is 30 a factor of n? [#permalink]

### Show Tags

04 Jan 2013, 07:51
Bunuel wrote:
daviesj wrote:
Is 30 a factor of n?

(1) 30 is a factor of the square of n
(2) 30 is a factor of 2n

I doubt on OA...plz clarify

Every GMAT divisibility question will tell you in advance that any unknowns represent positive integers, which means that ALL GMAT divisibility questions are limited to positive integers only.

If n is not an integer, then the question does not make sense (at least for GMAT) .

The question should read:
If n is an integer, is 30 a factor of n?

(1) 30 is a factor of n^2. If 30=2*3*5 is not a factor of n (if 2, 3 and 5 are not factors of n), then how this factors could appear in n^2? Exponentiation doesn't "produce" primes. Sufficient.

(2) 30 is a factor of 2n. Clearly insufficient: if n=15 then the answer is NO but if n=30 then the answer is YES. Not sufficient.

Hi Bunuel,

Just curious.. Why would the question not make sense if "n" were not an integer?
_________________

Did you find this post helpful?... Please let me know through the Kudos button.

Thanks To The Almighty - My GMAT Debrief

GMAT Reading Comprehension: 7 Most Common Passage Types

Current Student
Status: Never ever give up on yourself.Period.
Joined: 23 Aug 2012
Posts: 152
Location: India
Concentration: Finance, Human Resources
GMAT 1: 570 Q47 V21
GMAT 2: 690 Q50 V33
GPA: 3.5
WE: Information Technology (Investment Banking)
Followers: 9

Kudos [?]: 234 [0], given: 35

Re: Is 30 a factor of n? [#permalink]

### Show Tags

04 Jan 2013, 08:59
Thanks Bunuel,

I used the same logic as you did.
that's why I didn't get C as answer...Thanks for the clarification..+1 Kudos
_________________

Don't give up on yourself ever. Period.
Beat it, no one wants to be defeated (My journey from 570 to 690) : beat-it-no-one-wants-to-be-defeated-journey-570-to-149968.html

Intern
Joined: 16 Apr 2009
Posts: 16
Followers: 0

Kudos [?]: 9 [0], given: 5

Re: Is 30 a factor of n? [#permalink]

### Show Tags

04 Jan 2013, 23:12
Bunuel wrote:
daviesj wrote:
Is 30 a factor of n?

(1) 30 is a factor of the square of n
(2) 30 is a factor of 2n

I doubt on OA...plz clarify

Every GMAT divisibility question will tell you in advance that any unknowns represent positive integers, which means that ALL GMAT divisibility questions are limited to positive integers only.

If n is not an integer, then the question does not make sense (at least for GMAT) .

The question should read:
If n is an integer, is 30 a factor of n?

(1) 30 is a factor of n^2. If 30=2*3*5 is not a factor of n (if 2, 3 and 5 are not factors of n), then how this factors could appear in n^2? Exponentiation doesn't "produce" primes. Sufficient.

(2) 30 is a factor of 2n. Clearly insufficient: if n=15 then the answer is NO but if n=30 then the answer is YES. Not sufficient.

Bunnel-
Is it not possible that for Statement 1:

If the number is 900 and 30 is a factor of 900, then it is possible that 30 (which is ) is a factor of the square root of 900. In the contrary, 60 is also a factor of 900 but is not a factor of the square root of 900.

Please shed some light..
Thanks
Math Expert
Joined: 02 Sep 2009
Posts: 32531
Followers: 5624

Kudos [?]: 68230 [0], given: 9797

Re: Is 30 a factor of n? [#permalink]

### Show Tags

05 Jan 2013, 03:35
Expert's post
Drik wrote:
Bunuel wrote:
daviesj wrote:
Is 30 a factor of n?

(1) 30 is a factor of the square of n
(2) 30 is a factor of 2n

I doubt on OA...plz clarify

Every GMAT divisibility question will tell you in advance that any unknowns represent positive integers, which means that ALL GMAT divisibility questions are limited to positive integers only.

If n is not an integer, then the question does not make sense (at least for GMAT) .

The question should read:
If n is an integer, is 30 a factor of n?

(1) 30 is a factor of n^2. If 30=2*3*5 is not a factor of n (if 2, 3 and 5 are not factors of n), then how this factors could appear in n^2? Exponentiation doesn't "produce" primes. Sufficient.

(2) 30 is a factor of 2n. Clearly insufficient: if n=15 then the answer is NO but if n=30 then the answer is YES. Not sufficient.

Bunnel-
Is it not possible that for Statement 1:

If the number is 900 and 30 is a factor of 900, then it is possible that 30 (which is ) is a factor of the square root of 900. In the contrary, 60 is also a factor of 900 but is not a factor of the square root of 900.

Please shed some light..
Thanks

If prime number p is a factor of n^2 (where n is a positive integer), then p must be a factor of n.

So, the fact that 2, 3, and 5 are factors of n^2 means that 2, 3 and 5 must also be factors of n.

But if p^2 is a factor of n^2 (where n is a positive integer), then p^2 may or may not be a factor of n.

For example, if 60=2^2*3*5 is a factor of n^2, then all primes of 60 must also be factors of n, but 2^2 may or may not be a factor of n, so 60 may or may not be a factor of n.

Hope it's clear.
_________________
GMAT Club Legend
Joined: 09 Sep 2013
Posts: 9220
Followers: 453

Kudos [?]: 114 [0], given: 0

Re: Is 30 a factor of n? [#permalink]

### Show Tags

11 Nov 2014, 03:55
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________
Manager
Joined: 14 Jul 2014
Posts: 154
Followers: 1

Kudos [?]: 6 [0], given: 109

Re: Is 30 a factor of n? [#permalink]

### Show Tags

23 Mar 2016, 11:02
what is the correct answer? Bunuel says A but the answer is C?
Math Expert
Joined: 02 Sep 2009
Posts: 32531
Followers: 5624

Kudos [?]: 68230 [0], given: 9797

Re: Is 30 a factor of n? [#permalink]

### Show Tags

23 Mar 2016, 11:05
Expert's post
dina98 wrote:
what is the correct answer? Bunuel says A but the answer is C?

The answer is A. Edited the OA in the original post.
_________________
Intern
Joined: 16 Apr 2015
Posts: 28
Followers: 0

Kudos [?]: 8 [0], given: 114

Re: Is 30 a factor of n? [#permalink]

### Show Tags

23 Mar 2016, 11:39
Bunuel wrote:
daviesj wrote:
Is 30 a factor of n?

(1) 30 is a factor of the square of n
(2) 30 is a factor of 2n

I doubt on OA...plz clarify

Every GMAT divisibility question will tell you in advance that any unknowns represent positive integers, which means that ALL GMAT divisibility questions are limited to positive integers only.

If n is not an integer, then the question does not make sense (at least for GMAT) .

The question should read:
If n is an integer, is 30 a factor of n?

(1) 30 is a factor of n^2. If 30=2*3*5 is not a factor of n (if 2, 3 and 5 are not factors of n), then how this factors could appear in n^2? Exponentiation doesn't "produce" primes. Sufficient.

(2) 30 is a factor of 2n. Clearly insufficient: if n=15 then the answer is NO but if n=30 then the answer is YES. Not sufficient.

Hello Bunuel,
Is there a reference for your statement
Every GMAT divisibility question will tell you in advance that any unknowns represent positive integers, which means that ALL GMAT divisibility questions are limited to positive integers only.

somewhere in GMAT official guide. I am little confused here, because almost in every DS question we are told to not assume a number as +ve or as integer unless otherwise advised.

In my opinion, given in this question we must not assume that "n" is positive integer.
Intern
Joined: 16 Apr 2015
Posts: 28
Followers: 0

Kudos [?]: 8 [0], given: 114

Is 30 a factor of n? [#permalink]

### Show Tags

23 Mar 2016, 12:06
Quote:
I'm not saying that one should assume this. I'm saying that in its current form the question is NOT GMAT like because every GMAT divisibility question will tell you in advance that any unknowns represent positive integers. So, if it were proper GMAT question we would be given that n is an integer.

Thank Bunuel, this makes lot of sense and explain the question OA to me now.
Manager
Joined: 14 Jul 2014
Posts: 154
Followers: 1

Kudos [?]: 6 [0], given: 109

Re: Is 30 a factor of n? [#permalink]

### Show Tags

23 Mar 2016, 12:59
Bunuel, if we see a divisibility question and integer details are not mentioned, should we assume that it is an integer because GMAT does mention usually? (probably asking the same question the other user asked - just wanted to confirm)
Math Expert
Joined: 02 Sep 2009
Posts: 32531
Followers: 5624

Kudos [?]: 68230 [0], given: 9797

Re: Is 30 a factor of n? [#permalink]

### Show Tags

23 Mar 2016, 13:12
Expert's post
dina98 wrote:
Bunuel, if we see a divisibility question and integer details are not mentioned, should we assume that it is an integer because GMAT does mention usually? (probably asking the same question the other user asked - just wanted to confirm)

Proper GMAT question will always mention that variables in divisibility questions are positive integers.
_________________
Re: Is 30 a factor of n?   [#permalink] 23 Mar 2016, 13:12
Similar topics Replies Last post
Similar
Topics:
3 If F is the prime factorization of N!, how many factors in F have an e 5 09 Apr 2015, 07:33
2 If n is the integer, whether 30 is a factor of n? 3 26 Jan 2012, 06:38
6 If the greatest common factor of two integers, m and n, is 12 20 Mar 2011, 09:52
8 If N is a positive integer, is 9 a factor of N? 9 24 May 2010, 22:58
6 If n and t are positive integers, is n a factor of t? 6 30 Jul 2009, 04:35
Display posts from previous: Sort by

# Is 30 a factor of n?

 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®.