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

It is currently 25 May 2019, 21:35

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.

Close

Request Expert Reply

Confirm Cancel

Is the integer x divisible by 36? (1) x is divisible by 12

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
Senior Manager
Senior Manager
User avatar
B
Status: No dream is too large, no dreamer is too small
Joined: 14 Jul 2010
Posts: 498
Is the integer x divisible by 36? (1) x is divisible by 12  [#permalink]

Show Tags

New post 22 Feb 2011, 11:28
1
00:00
A
B
C
D
E

Difficulty:

  5% (low)

Question Stats:

88% (00:30) correct 13% (00:27) wrong based on 79 sessions

HideShow timer Statistics

Is the integer x divisible by 36 ?

(1) x is divisible by 12.
(2) x is divisible by 9.

OPEN DISCUSSION OF THIS QUESTION IS HERE: http://gmatclub.com/forum/is-the-intege ... 67497.html


My approach was as follows
(1)24, 48 is divisible by 12 but not by 36 so NS
(2) 27, 81 is divisible by 9 but noty 36. So NS

considering two: the integer which is divisible by 12 and 9 is multiple 3 and 36 is multiple 3. So any digit divisible 12 and 9 is also divisible by 36.

Please help with good approach.


--== Message from the GMAT Club Team ==--

THERE IS LIKELY A BETTER DISCUSSION OF THIS EXACT QUESTION.
This discussion does not meet community quality standards. It has been retired.


If you would like to discuss this question please re-post it in the respective forum. Thank you!

To review the GMAT Club's Forums Posting Guidelines, please follow these links: Quantitative | Verbal Please note - we may remove posts that do not follow our posting guidelines. Thank you.

_________________
Retired Moderator
avatar
Joined: 20 Dec 2010
Posts: 1772
Re: Is the integer x divisible by 36? (1) x is divisible by 12  [#permalink]

Show Tags

New post 22 Feb 2011, 11:41
Prime factors of \(36 = 2^2*3^2\)

So if x is divided by a number whose factors at least comprise of all the prime factors of 36; i.e. two 2's and two 3's then x will be divisible by 36.

1.Prime factors of 12 = 2^2*3
So; only two 2's and one 3. We require 2 two's and two 3's for the number to be divisible by 36.
Not Sufficient.


2.Prime factors of 9 = 3^2
So; only two 3's. We require 2 two's and two 3's for the number to be divisible by 36.
Not Sufficient.

Combining both;
x is divisible by; 2^2*3*3^2
The factors comprise of at least two 2's and two 3's. Must be divisible by 36.
Sufficient.

Ans: "C"
_________________
Manager
Manager
User avatar
Joined: 17 Feb 2011
Posts: 143
Concentration: Real Estate, Finance
Schools: MIT (Sloan) - Class of 2014
GMAT 1: 760 Q50 V44
Re: Is the integer x divisible by 36? (1) x is divisible by 12  [#permalink]

Show Tags

New post 23 Feb 2011, 13:41
Mate, you can download my flashcards and take a look at slides 81-84. All the approaches to find GCF and LCM are there. Hope it helps.

Link: my-comprehensive-quant-flashcards-109836.html

Solving the question:
Always find the prime factors, as fluke showed. Then, remember that GCF is formed by the shared prime factors.

The 36's prime factors box has: 2, 2, 3, 3

(1) 12's prime box has 2, 2, 3. A 3 is missing, so not sufficient

(2) 9's prime box has 3, 3. Not sufficient as well (two 2's missing)

If you combine them, you will have two shared 2's and two shared 3's, which are the same as the prime factors of 36. So, both are sufficient. A number that is divisible by 9 and by 12 will also be divisible by 36.

Cheers
Manager
Manager
avatar
Joined: 07 Jun 2010
Posts: 81
Re: Is the integer x divisible by 36? (1) x is divisible by 12  [#permalink]

Show Tags

New post 23 Feb 2011, 19:32
Find whether 36 is factor of X......

Break down 36 to prime factors....2*2*3*3

If 36 is factor of x, then the 2*2*3*3 are factors (equivalent)

This is true if we know other factors that also exhaust the prime factors.

A. 12 is a factor of x. 2*3*2 are the prime factors. This covers all the factors of 36 except for the second 3. We don't have proof that x has a second 3 as a factors so A is insufficient

B. 9 is a prime factors. 3*3 are the prime factors. This covers only 3*3 and doesn't tell us whether 2*2 are also factors. Insufficient.

Both A&B tells us that we have 3*3 and 3*2*2 as factors.

The maximum number of a certain prime factor need to come from one of the factors, as it does. Both 3's come from the 9, both 2s come from the 12. Sufficient C
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 55274
Re: Is the integer x divisible by 36? (1) x is divisible by 12  [#permalink]

Show Tags

New post 16 Aug 2017, 09:23
Is the integer x divisible by 36 ?

(1) x is divisible by 12. If x=12, then the answer is NO but if x=36, then the answer is YES. Not sufficient.

(2) x is divisible by 9. If x=9, then the answer is NO but if x=36, then the answer is YES. Not sufficient.

(1)+(2) From above it follows that x must be divisible by the least common multiple of 12 and 9, which is 36. Sufficient.

Answer: C.

OPEN DISCUSSION OF THIS QUESTION IS HERE: http://gmatclub.com/forum/is-the-intege ... 67497.html

--== Message from the GMAT Club Team ==--

THERE IS LIKELY A BETTER DISCUSSION OF THIS EXACT QUESTION.
This discussion does not meet community quality standards. It has been retired.


If you would like to discuss this question please re-post it in the respective forum. Thank you!

To review the GMAT Club's Forums Posting Guidelines, please follow these links: Quantitative | Verbal Please note - we may remove posts that do not follow our posting guidelines. Thank you.

_________________
GMAT Club Bot
Re: Is the integer x divisible by 36? (1) x is divisible by 12   [#permalink] 16 Aug 2017, 09:23
Display posts from previous: Sort by

Is the integer x divisible by 36? (1) x is divisible by 12

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  


Copyright

GMAT Club MBA Forum Home| About| Terms and Conditions and Privacy Policy| GMAT Club Rules| Contact| Sitemap

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne

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®.