Is positive integer n 1 a multiple of 3? (1) n^3 n is a

Oldest

Best Reply

Author

Message

TAGS:

Manager

Joined: 23 May 2007

Posts: 109

Followers: 1

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

Is positive integer n 1 a multiple of 3? (1) n^3 n is a [#permalink]

09 Jul 2007, 20:33

00:00

Question Stats:

0% (00:00) correct

0% (00:00) wrong

based on 0 sessions

Is positive integer n – 1 a multiple of 3?

(1) n^3 – n is a multiple of 3

(2) n^3 + 2n^2+ n is a multiple of 3

Manager

Joined: 07 Feb 2007

Posts: 212

Followers: 1

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

Re: DS Question [#permalink]

10 Jul 2007, 05:42

Himalayan wrote:

dreamgmat1 wrote:

Is positive integer n – 1 a multiple of 3?

(1) n^3 – n is a multiple of 3

(2) n^3 + 2n^2+ n is a multiple of 3

Sorry, I made a mistake. B is right.
(2) n^3+2n^2+n=n*(n+1)^2
--> n=3a or n=3a-1, where a is a positive integer
--> n-1= 3a-1 or n-1=3a-2, none of which is a multiple of 3.
--> Sufficient.

The exaplanation relates to the link below:
http://www.gmatclub.com/phpbb/viewtopic.php?t=48376.

Last edited by wudy on 10 Jul 2007, 09:18, edited 1 time in total.

Manager

Joined: 12 Apr 2007

Posts: 171

Followers: 1

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

[#permalink]

10 Jul 2007, 07:02

i'll go with B here too

S2: n(n+1)^2

this means either n or n+1 is a mult of 3. if this is the case, there is no way n-1 can be a mult of 3.

Director

Joined: 16 May 2007

Posts: 552

Followers: 3

Kudos [?]: 10 [0], given: 0

[#permalink]

10 Jul 2007, 08:51

I will go with E. Picking up numbers will help. Pick up n =3 and you will see both statements are insuff.

Manager

Joined: 12 Apr 2007

Posts: 171

Followers: 1

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

[#permalink]

10 Jul 2007, 09:22

trahul4 wrote:

I will go with E. Picking up numbers will help. Pick up n =3 and you will see both statements are insuff.

What is an example for S2 where the answer is yes?

Manager

Joined: 07 Feb 2007

Posts: 212

Followers: 1

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

[#permalink]

10 Jul 2007, 09:24

trahul4 wrote:

I will go with E. Picking up numbers will help. Pick up n =3 and you will see both statements are insuff.

Please check the above link. E is not the answer, although at first I got E too. :oops:

Manager

Joined: 23 May 2007

Posts: 109

Followers: 1

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

[#permalink]

10 Jul 2007, 21:24

OA is B

Any three consecutive positive integers include exactly one multiple of 3

[#permalink] 10 Jul 2007, 21:24

		Similar topics	Author	Replies	Last post
Similar Topics:		Is positive integer n 1 a multiple of 3? (1) n^3 n is a	ArvGMAT	2	27 Jun 2007, 21:12
		Is positive integer n 1 a multiple of 3? (1) n3 n is a	JDMBA	6	25 Nov 2007, 10:52
	3	Is positive integer n 1 a multiple of 3? (1) n^3 n is a	JCLEONES	7	15 Jan 2008, 16:37
		Is positive integer n 1 a multiple of 3? (1) n^3 n is a	suntaurian	3	17 Feb 2008, 12:49
	3	Is positive integer n 1 a multiple of 3? (1) n^3 n is a	Orange08	3	25 Sep 2010, 11:06

Is positive integer n 1 a multiple of 3? (1) n^3 n is a

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.

GMAT Courses

Admissions Consulting

Is positive integer n 1 a multiple of 3? (1) n^3 n is a

Is positive integer n 1 a multiple of 3? (1) n^3 n is a

Main navigation

GMAT Resources

Partners

MBA Resources