GMAT Question of the Day - Daily to your Mailbox; hard ones only

 It is currently 18 Jun 2018, 13:58

### 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

# The number 18^5 is NOT divisible by:

Author Message
TAGS:

### Hide Tags

Intern
Joined: 31 Jan 2018
Posts: 9
The number 18^5 is NOT divisible by: [#permalink]

### Show Tags

03 Feb 2018, 22:09
00:00

Difficulty:

25% (medium)

Question Stats:

74% (00:52) correct 26% (01:17) wrong based on 34 sessions

### HideShow timer Statistics

The number 18^5 is NOT divisible by:

A. 32
B. 60
C. 108
D. 144
E. 324
Math Expert
Joined: 02 Aug 2009
Posts: 5887
Re: The number 18^5 is NOT divisible by: [#permalink]

### Show Tags

03 Feb 2018, 23:03
ggpapas wrote:
The number 18^5 is NOT divisble by:
A.32
B.60
C.108
D.144
E.324

18^5= 2^5*9^5=2^5*3^10..

We can check the factors of choices now..
But clearly 5 is not a factor of 18^5, so 60 cannot evenly divide it..

B
_________________

Absolute modulus :http://gmatclub.com/forum/absolute-modulus-a-better-understanding-210849.html#p1622372
Combination of similar and dissimilar things : http://gmatclub.com/forum/topic215915.html

GMAT online Tutor

BSchool Forum Moderator
Joined: 26 Feb 2016
Posts: 2804
Location: India
GPA: 3.12
Re: The number 18^5 is NOT divisible by: [#permalink]

### Show Tags

04 Feb 2018, 10:43
ggpapas wrote:
The number 18^5 is NOT divisible by:

A. 32
B. 60
C. 108
D. 144
E. 324

In order to solve these kind of problems, we need to prime factorize
the number and the answer options.

Since we have been asked to check which answer option is not divisible,
we would have to find an answer option which on prime-factorization
contains a factor which does not divide the number

Number(when prime factorized) - $$18^5 = (2*3^2)^5 = 2^5 * 3^{10}$$

A. $$32 - 2^5$$
B. $$60 - 2^2 * 3 * 5$$
C. $$108 - 2^2 *3^3$$
D. $$144 - 2^4 * 3^2$$
E. $$324 - 2^2 *3^4$$

Since 60 contains a 5 which is not present in the number, it will not divide(Option B)
_________________

You've got what it takes, but it will take everything you've got

Re: The number 18^5 is NOT divisible by:   [#permalink] 04 Feb 2018, 10:43
Display posts from previous: Sort by