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

It is currently 24 Jul 2014, 04:17

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

An integer greater than 1 that is not prime is called

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
Manager
Manager
User avatar
Joined: 04 Jan 2008
Posts: 120
Followers: 2

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

An integer greater than 1 that is not prime is called [#permalink] New post 10 Sep 2008, 00:05
00:00
A
B
C
D
E

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 0 sessions
An integer greater than 1 that is not prime is called composite. If the two-digit integer n is greater than 20, is n composite?

(1) The tens digit of n is a factor of the units digit of n.
(2) The tens digit of n is 2.
Director
Director
avatar
Joined: 23 Sep 2007
Posts: 798
Followers: 5

Kudos [?]: 73 [0], given: 0

GMAT Tests User
Re: Zumit DS 015 [#permalink] New post 10 Sep 2008, 00:44
dancinggeometry wrote:
An integer greater than 1 that is not prime is called composite. If the two-digit integer n is greater than 20, is n composite?

(1) The tens digit of n is a factor of the units digit of n.
(2) The tens digit of n is 2.



C

the number is even

not a because the number can be 24 or 113
SVP
SVP
avatar
Joined: 17 Jun 2008
Posts: 1580
Followers: 11

Kudos [?]: 174 [0], given: 0

GMAT Tests User
Re: Zumit DS 015 [#permalink] New post 10 Sep 2008, 04:06
gmatnub wrote:
dancinggeometry wrote:
An integer greater than 1 that is not prime is called composite. If the two-digit integer n is greater than 20, is n composite?

(1) The tens digit of n is a factor of the units digit of n.
(2) The tens digit of n is 2.



C

the number is even

not a because the number can be 24 or 113


That is not true. n is a two digit integer greater than 20....hence A should be sufficient.
Manager
Manager
User avatar
Joined: 09 Jul 2007
Posts: 244
Followers: 2

Kudos [?]: 43 [0], given: 0

GMAT Tests User
Re: Zumit DS 015 [#permalink] New post 10 Sep 2008, 04:15
IMO A.

(1) The tens digit of n is a factor of the units digit of n >

lets consider the number is 10X +y ; it says Y=kX.. so the number will becose 10X+KX = X (10 +k) which will be a composite number unless X=1 ; now X can not be 1 as 10X+Y> 20

also if you read this option properly the, number shoul be 10X+Y < 49

(2) The tens digit of n is 2.
Senior Manager
Senior Manager
User avatar
Joined: 04 Jan 2006
Posts: 280
Followers: 1

Kudos [?]: 17 [0], given: 0

GMAT Tests User
Re: Zumit DS 015 [#permalink] New post 10 Sep 2008, 11:46
dancinggeometry wrote:
An integer greater than 1 that is not prime is called composite. If the two-digit integer n is greater than 20, is n composite?

(1) The tens digit of n is a factor of the units digit of n.
(2) The tens digit of n is 2.


Good question! :shock:

Basically this question want to know whether n is prime.

Let's assume that n = 10a + b

1) Since b = ax, n = 10a + ax = a*(10+x)
n cannot be prime because it has more than one factor. Or n is a composite. SUFF

2) n = 20 + b
b can be any number from 1 to 9. Some are prime and some are composite. INSUFF
Director
Director
User avatar
Joined: 26 Jul 2007
Posts: 541
Schools: Stern, McCombs, Marshall, Wharton
Followers: 4

Kudos [?]: 94 [0], given: 0

GMAT Tests User
Re: Zumit DS 015 [#permalink] New post 10 Sep 2008, 11:46
I got A as well but I had to think through it.

(1) The tens digit of n is a factor of the units digit of n.

If 9, factors are 9,3,1 = 19,39,99
If 8, factors are 8,4,2,1 = 18,28,48,88
If 7, factors are 7,1 = 17,77
If 6, factors are 6,3,2,1 = 16,26,36,66
If 5, factors are 5,1 = 15,55
If 4, factors are 4,2,1 = 14,24,44
If 3, factors are 3,1 = 13,33
If 2, factors are 2,1 = 12,22
If 1, factors are 1 = 11

None of the # above 20 are prime, so it is composite.
Manager
Manager
avatar
Joined: 07 Jan 2008
Posts: 76
Followers: 1

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

Re: Zumit DS 015 [#permalink] New post 10 Sep 2008, 13:10
A

(1) The tens digit of n is a factor of the units digit of n.
ex: any number greater than 20, and tens digit is a factor of the units digit.
24, 26, 28, 36,33....none r prime...so they have to be composite

So, A is sufficient

(2) The tens digit of n is 2.
ex: 21,22,23,24,25....could be prime or composite

So, B is not sufficient...
VP
VP
User avatar
Joined: 30 Jun 2008
Posts: 1048
Followers: 11

Kudos [?]: 260 [0], given: 1

GMAT Tests User
Re: Zumit DS 015 [#permalink] New post 10 Sep 2008, 22:07
Good question indeed ... I decided the answer was C before reading through the solutions below... I guess I need to be more careful with DS ....
_________________

"You have to find it. No one else can find it for you." - Bjorn Borg

Check out my GMAT blog - GMAT Tips and Strategies

Manager
Manager
avatar
Joined: 14 Jun 2007
Posts: 171
Location: Vienna, Austria
Followers: 1

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

GMAT Tests User
Re: Zumit DS 015 [#permalink] New post 11 Sep 2008, 00:30
guys, do we have an OA? A & C are very temptative ...........
Manager
Manager
User avatar
Joined: 04 Jan 2008
Posts: 120
Followers: 2

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

Re: Zumit DS 015 [#permalink] New post 11 Sep 2008, 01:39
OA is A. Bin 4 problem.
VP
VP
User avatar
Joined: 30 Jun 2008
Posts: 1048
Followers: 11

Kudos [?]: 260 [0], given: 1

GMAT Tests User
Re: Zumit DS 015 [#permalink] New post 11 Sep 2008, 02:10
What is the source of these problems ?
_________________

"You have to find it. No one else can find it for you." - Bjorn Borg

Check out my GMAT blog - GMAT Tips and Strategies

VP
VP
avatar
Joined: 17 Jun 2008
Posts: 1406
Followers: 7

Kudos [?]: 108 [0], given: 0

GMAT Tests User
Re: Zumit DS 015 [#permalink] New post 14 Sep 2008, 03:53
dancinggeometry wrote:
An integer greater than 1 that is not prime is called composite. If the two-digit integer n is greater than 20, is n composite?

(1) The tens digit of n is a factor of the units digit of n.
(2) The tens digit of n is 2.


1) answers since n=10p+q and p is a factor of q

n=10p+pm div by p
COMPOSITE SUFFI

2)23 is a prime 24 is a composite
INSUFFI
IMO A
_________________

cheers
Its Now Or Never

VP
VP
avatar
Joined: 17 Jun 2008
Posts: 1406
Followers: 7

Kudos [?]: 108 [0], given: 0

GMAT Tests User
Re: Zumit DS 015 [#permalink] New post 14 Sep 2008, 03:55
dancinggeometry wrote:
OA is A. Bin 4 problem.

Whats the source of these questions ?
_________________

cheers
Its Now Or Never

VP
VP
User avatar
Joined: 05 Jul 2008
Posts: 1436
Followers: 33

Kudos [?]: 209 [0], given: 1

GMAT Tests User
Re: Zumit DS 015 [#permalink] New post 14 Sep 2008, 15:11
spriya wrote:
dancinggeometry wrote:
OA is A. Bin 4 problem.

Whats the source of these questions ?



With A, the values can be only 22,24,26,28,33,36,39,44,48,55,66,77,88,99

All these are composite. We have a Yes, Suff

With B, 21,22,23 We have yes and no. Insuff

hence A
Re: Zumit DS 015   [#permalink] 14 Sep 2008, 15:11
    Similar topics Author Replies Last post
Similar
Topics:
An integer greater than 1 that is not prime is called jade3 3 17 Nov 2009, 23:11
An integer greater than 1 that is not prime is called ritula 10 19 Jun 2008, 23:14
6 Experts publish their posts in the topic An integer greater than 1 that is not prime is called marcodonzelli 9 08 Jan 2008, 05:20
Problem 1 : An integer greater than 1 that is not a prime is briozeal 5 12 Jun 2006, 15:41
An integer greater than 1 that is not a prime is called gmat_crack 11 03 May 2006, 14:41
Display posts from previous: Sort by

An integer greater than 1 that is not prime is called

  Question banks Downloads My Bookmarks Reviews Important topics  


cron

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®.