An integer greater than 1 that is not a prime is called : DS Archive
Check GMAT Club Decision Tracker for the Latest School Decision Releases http://gmatclub.com/AppTrack

 It is currently 23 Jan 2017, 04:21

### 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

# An integer greater than 1 that is not a prime is called

Author Message
Senior Manager
Joined: 22 Nov 2005
Posts: 476
Followers: 2

Kudos [?]: 20 [0], given: 0

An integer greater than 1 that is not a prime is called [#permalink]

### Show Tags

03 May 2006, 14:41
00:00

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.

An integer greater than 1 that is not a prime is called composite.
If the two digit integer n is greater than 20, is n composite ?

1. The tenths digit of n is a factor of the unit digits of n
2. The tenths digit of n is 2

I've a confusion, whether "tenths" and tens" digit is are same
Manager
Joined: 20 Mar 2005
Posts: 201
Location: Colombia, South America
Followers: 1

Kudos [?]: 16 [0], given: 0

Re: DS - Number theory [#permalink]

### Show Tags

03 May 2006, 14:52
gmat_crack wrote:
An integer greater than 1 that is not a prime is called composite.
If the two digit integer n is greater than 20, is n composite ?

1. The tenths digit of n is a factor of the unit digits of n
2. The tenths digit of n is 2

from the statement we know n is between 21-99

from (1)
we get that n can be 2x, 3x, 4x

so the numbers can be 22, 24, 26, 28, 33, 36,39, 44, 48

so (1) is sufficient

from (2) not enough could be 23 or 24 or whatever

so I'll go with A on this one
Manager
Joined: 14 Mar 2006
Posts: 208
Followers: 2

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

Re: DS - Number theory [#permalink]

### Show Tags

03 May 2006, 20:00
gmat_crack wrote:
An integer greater than 1 that is not a prime is called composite.
If the two digit integer n is greater than 20, is n composite ?

1. The tenths digit of n is a factor of the unit digits of n
2. The tenths digit of n is 2

I've a confusion, whether "tenths" and tens" digit is are same

'tenths' digit is the first digit after the decimal point (right of decimal point)
'tens' digit is the second digit before the decimal point (left of the decimal pont) 24, in this case 2 is the tens digit. hope this helps.
Manager
Joined: 14 Mar 2006
Posts: 208
Followers: 2

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

Re: DS - Number theory [#permalink]

### Show Tags

03 May 2006, 20:04
shampoo wrote:
gmat_crack wrote:
An integer greater than 1 that is not a prime is called composite.
If the two digit integer n is greater than 20, is n composite ?

1. The tenths digit of n is a factor of the unit digits of n
2. The tenths digit of n is 2

I've a confusion, whether "tenths" and tens" digit is are same

'tenths' digit is the first digit after the decimal point (right of decimal point)
'tens' digit is the second digit before the decimal point (left of the decimal pont) 24, in this case 2 is the tens digit. hope this helps.

Note: the above is a general rule, however, in this problem it seems that tenths refers to tens. someone correct me if I am wrong. thanks
Senior Manager
Joined: 29 Jun 2005
Posts: 403
Followers: 2

Kudos [?]: 21 [0], given: 0

### Show Tags

05 May 2006, 04:09
indeed A
From st 1 it can be only such integers as 24, 36, 48 etc….all of them are composite. Suff.
From st 2 it can be 26 or 29. So insuff.
Director
Joined: 24 Oct 2005
Posts: 659
Location: London
Followers: 1

Kudos [?]: 15 [0], given: 0

### Show Tags

05 May 2006, 04:47
Statement 1 is insufficient
Eg 13, 17 etc.
1 is a factor of 3.

Statement 2 is insufficient
23 is a prime no

Taking 1 and 2 together,
It can only be composite

Ans = C
VP
Joined: 29 Dec 2005
Posts: 1348
Followers: 10

Kudos [?]: 60 [0], given: 0

### Show Tags

05 May 2006, 05:16
remgeo wrote:
Statement 1 is insufficient
Eg 13, 17 etc.
1 is a factor of 3.

Statement 2 is insufficient
23 is a prime no

Taking 1 and 2 together,
It can only be composite

Ans = C

hmm...
A is sufficient. the question stem says n is greater than 20.
Quote:
An integer greater than 1 that is not a prime is called composite. If the two digit integer n is greater than 20, is n composite ?

1. The tenths digit of n is a factor of the unit digits of n
2. The tenths digit of n is 2
Director
Joined: 24 Oct 2005
Posts: 659
Location: London
Followers: 1

Kudos [?]: 15 [0], given: 0

### Show Tags

05 May 2006, 06:23
Yes...

God!! Help me ..........
Manager
Joined: 27 Jan 2006
Posts: 156
Location: Europe
Followers: 1

Kudos [?]: 3 [0], given: 0

### Show Tags

05 May 2006, 13:49

anybody who can break it??
VP
Joined: 29 Apr 2003
Posts: 1403
Followers: 2

Kudos [?]: 28 [0], given: 0

### Show Tags

05 May 2006, 18:46
jeunesis wrote:
:shock:

anybody who can break it??

Okay let me take a stab!

Let the number be of digits xy where x is the 10th digit and y the units. BOTH positive numbers as n>20!

Thus the number: n = 10*x+y

now the stem says that x is a multiple of y!!!
Thus we can rephrase y=mx

Substitute this in the number, we get:

n = 10*x + y
= 10*x + mx
= x(10+m)

Thus, the number n is divisible by some number x!
Since, the number is greater than 20, x is NOT 1!

Thus the number is divisible by some number that is not 1 and hence is not a PRIME number!

One might argue what if n=x! In such a scenario, we get the value of m as -ve!

Hence, I still favor option A!
VP
Joined: 29 Apr 2003
Posts: 1403
Followers: 2

Kudos [?]: 28 [0], given: 0

### Show Tags

05 May 2006, 19:16
Using brute force

from A:
22, 24, 26, 28
33, 36, 39
44, 48
55
66
77
88
99

All of them are composite!
Manager
Joined: 27 Mar 2006
Posts: 136
Followers: 1

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

### Show Tags

05 May 2006, 21:43
I agree with A
05 May 2006, 21:43
Display posts from previous: Sort by