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

It is currently 22 Jul 2018, 17:05

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

The HCF of 2472, 1284 and a third number ‘N’ is 12. If their LCM

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:

Hide Tags

1 KUDOS received
GMAT Forum Moderator
avatar
V
Joined: 28 May 2014
Posts: 528
GMAT 1: 730 Q49 V41
GMAT ToolKit User Premium Member
The HCF of 2472, 1284 and a third number ‘N’ is 12. If their LCM  [#permalink]

Show Tags

New post 23 Jan 2017, 12:23
1
5
00:00
A
B
C
D
E

Difficulty:

  85% (hard)

Question Stats:

51% (01:36) correct 49% (02:07) wrong based on 119 sessions

HideShow timer Statistics

The HCF of 2472, 1284 and a third number ‘N’ is 12. If their LCM is 2^3 × 3^2 × 5 × 103 × 107,
then the number ‘N’ is:

(A) 2^2 × 3^2 × 7
(B) 2^2 × 3^3 × 103
(C) 2^2 × 3^2 × 5
(D) 2^2 × 3 × 5
(E) None of these

_________________

440 to 730: If I Can, You Can Too

Senior Manager
Senior Manager
avatar
B
Joined: 13 Oct 2016
Posts: 367
GPA: 3.98
Re: The HCF of 2472, 1284 and a third number ‘N’ is 12. If their LCM  [#permalink]

Show Tags

New post 23 Jan 2017, 13:08
2
saswata4s wrote:
The HCF of 2472, 1284 and a third number ‘N’ is 12. If their LCM is 2^3 × 3^2 × 5 × 103 × 107,
then the number ‘N’ is:

(A) 2^2 × 3^2 × 7
(B) 2^2 × 3^3 × 103
(C) 2^2 × 3^2 × 5
(D) 2^2 × 3 × 5
(E) None of these



\(LCM (2472, 1284, N) = 2^3 × 3^2 × 5 × 103 × 107\)

\(2472 = 2^3*3*103\)

\(1284 = 2^2*3*107\)

In order to produce required LCM our N should have 3^2 and 5, because none of the 2472 and 1284 have them.

Only option that fits is C.
Intern
Intern
avatar
Joined: 25 Sep 2017
Posts: 3
The HCF of 2472, 1284 and a third number ‘N’ is 12. If their LCM  [#permalink]

Show Tags

New post Updated on: 22 Oct 2017, 09:48
HCF = 12 = 2^2 x 3
LCM = 2^3 × 3^2 × 5 × 103 × 107

2472 = 2^3 x 3 x 103
1284 = 2^2 x 3 x 107

Since we know, Product of LCM and HCF = Product of Numbers

(2^2 x 3) x (2^3 x 3^2 x 5 x 103 x 107) = (2^3 x 3 x 103) x ( 2^2 x 3 x 107) x N

2^5 x 3^3 x 5 = 2^5 x 3^2 x N

3 x 5 = N

So N is 3*5 and answer is E (None of the Above)

Edited: And, I realised that below formula is applicable only when there are two numbers. If there are more than two numbers then their HCF should be 1(they should be prime numbers).
Product of LCM and HCF = Product of Numbers

Hence above solution is incorrect.

Originally posted by ramanbajwa2003 on 03 Oct 2017, 06:26.
Last edited by ramanbajwa2003 on 22 Oct 2017, 09:48, edited 1 time in total.
Intern
Intern
avatar
B
Joined: 08 Nov 2015
Posts: 8
Re: The HCF of 2472, 1284 and a third number ‘N’ is 12. If their LCM  [#permalink]

Show Tags

New post 21 Oct 2017, 05:33
ramanbajwa2003 wrote:
HCF = 12 = 2^2 x 3
LCM = 2^3 × 3^2 × 5 × 103 × 107

2472 = 2^3 x 3 x 103
1284 = 2^2 x 3 x 107

Since we know, Product of LCM and HCF = Product of Numbers

(2^2 x 3) x (2^3 x 3^2 x 5 x 103 x 107) = (2^3 x 3 x 103) x ( 2^2 x 3 x 107) x N

2^5 x 3^3 x 5 = 2^5 x 3^2 x N

3 x 5 = N

So N is 3*5 and answer is E (None of the Above)


Hi Raman,

If N is 15, then how can it have HCF as 12?
Senior Manager
Senior Manager
avatar
G
Joined: 31 Jul 2017
Posts: 382
Location: Malaysia
WE: Consulting (Energy and Utilities)
Re: The HCF of 2472, 1284 and a third number ‘N’ is 12. If their LCM  [#permalink]

Show Tags

New post 21 Oct 2017, 07:21
ramanbajwa2003 wrote:
HCF = 12 = 2^2 x 3
LCM = 2^3 × 3^2 × 5 × 103 × 107

2472 = 2^3 x 3 x 103
1284 = 2^2 x 3 x 107

Since we know, Product of LCM and HCF = Product of Numbers

(2^2 x 3) x (2^3 x 3^2 x 5 x 103 x 107) = (2^3 x 3 x 103) x ( 2^2 x 3 x 107) x N

2^5 x 3^3 x 5 = 2^5 x 3^2 x N

3 x 5 = N

So N is 3*5 and answer is E (None of the Above)


We cannot use this logic as:

Product of two numbers = Product of their H.C.F. and L.C.M.
_________________

If my Post helps you in Gaining Knowledge, Help me with KUDOS.. !!

Intern
Intern
avatar
B
Joined: 18 Nov 2017
Posts: 41
Re: The HCF of 2472, 1284 and a third number ‘N’ is 12. If their LCM  [#permalink]

Show Tags

New post 25 Jun 2018, 01:50
saswata4s wrote:
The HCF of 2472, 1284 and a third number ‘N’ is 12. If their LCM is 2^3 × 3^2 × 5 × 103 × 107,
then the number ‘N’ is:

(A) 2^2 × 3^2 × 7
(B) 2^2 × 3^3 × 103
(C) 2^2 × 3^2 × 5
(D) 2^2 × 3 × 5
(E) None of these



Hi Bunuel,

Could you please explain how to get to the answer?

Thanks!
Re: The HCF of 2472, 1284 and a third number ‘N’ is 12. If their LCM &nbs [#permalink] 25 Jun 2018, 01:50
Display posts from previous: Sort by

The HCF of 2472, 1284 and a third number ‘N’ is 12. If their LCM

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

Events & Promotions

PREV
NEXT


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®.