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

It is currently 24 Apr 2019, 05:49

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

If (10!)/(2y) is an odd integer, what is y?

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

Hide Tags

 
Retired Moderator
avatar
Joined: 29 Apr 2015
Posts: 838
Location: Switzerland
Concentration: Economics, Finance
Schools: LBS MIF '19
WE: Asset Management (Investment Banking)
GMAT ToolKit User
If (10!)/(2y) is an odd integer, what is y?  [#permalink]

Show Tags

New post 03 Oct 2015, 02:47
3
00:00
A
B
C
D
E

Difficulty:

  25% (medium)

Question Stats:

74% (01:11) correct 26% (01:49) wrong based on 135 sessions

HideShow timer Statistics

If \(\frac{10!}{2^y}\) is an odd integer, what is y?

A. 5
B. 6
C. 7
D. 8
E. 10

_________________
Saving was yesterday, heat up the gmatclub.forum's sentiment by spending KUDOS!

PS Please send me PM if I do not respond to your question within 24 hours.
CEO
CEO
avatar
S
Joined: 20 Mar 2014
Posts: 2624
Concentration: Finance, Strategy
Schools: Kellogg '18 (M)
GMAT 1: 750 Q49 V44
GPA: 3.7
WE: Engineering (Aerospace and Defense)
GMAT ToolKit User Reviews Badge
Re: If (10!)/(2y) is an odd integer, what is y?  [#permalink]

Show Tags

New post 03 Oct 2015, 03:30
reto wrote:
If (10!)/(2y) is an odd integer, what is y?

A. 5
B. 6
C. 7
D. 8
E. 10


reto, check the question.

10!/16 will still give you an even integer. 10! has 2^8 in it and for obtaining an odd integer when you divide 10! by another integer, you need to cancel out all 8 2s.
Retired Moderator
avatar
Joined: 29 Apr 2015
Posts: 838
Location: Switzerland
Concentration: Economics, Finance
Schools: LBS MIF '19
WE: Asset Management (Investment Banking)
GMAT ToolKit User
Re: If (10!)/(2y) is an odd integer, what is y?  [#permalink]

Show Tags

New post 03 Oct 2015, 03:51
Engr2012 wrote:
reto wrote:
If (10!)/(2y) is an odd integer, what is y?

A. 5
B. 6
C. 7
D. 8
E. 10


reto, check the question.

10!/16 will still give you an even integer. 10! has 2^8 in it and for obtaining an odd integer when you divide 10! by another integer, you need to cancel out all 8 2s.


Thanks it's done. You are very attentive!
_________________
Saving was yesterday, heat up the gmatclub.forum's sentiment by spending KUDOS!

PS Please send me PM if I do not respond to your question within 24 hours.
CEO
CEO
User avatar
D
Status: GMATINSIGHT Tutor
Joined: 08 Jul 2010
Posts: 2908
Location: India
GMAT: INSIGHT
Schools: Darden '21
WE: Education (Education)
Reviews Badge
Re: If (10!)/(2y) is an odd integer, what is y?  [#permalink]

Show Tags

New post 03 Oct 2015, 04:34
1
reto wrote:
If \(\frac{10!}{2^y}\) is an odd integer, what is y?

A. 5
B. 6
C. 7
D. 8
E. 10


10! = 1*2*3*4*5*6*7*8*9*10

For calculating the power of 2 in 10!

\(2*4*6*8*10 have 2^1*2^2*2^1*2^3*2^1 = 2^8\)

i.e. \(10! = 2^8*Odd Numbers\)

Hence, 10!/2^8 will be an Odd Integer

Answer: option D
_________________
Prosper!!!
GMATinsight
Bhoopendra Singh and Dr.Sushma Jha
e-mail: info@GMATinsight.com I Call us : +91-9999687183 / 9891333772
Online One-on-One Skype based classes and Classroom Coaching in South and West Delhi
http://www.GMATinsight.com/testimonials.html

ACCESS FREE GMAT TESTS HERE:22 ONLINE FREE (FULL LENGTH) GMAT CAT (PRACTICE TESTS) LINK COLLECTION
Intern
Intern
User avatar
Joined: 01 Nov 2015
Posts: 36
Location: India
Concentration: Marketing, Entrepreneurship
WE: Engineering (Computer Software)
Re: If (10!)/(2y) is an odd integer, what is y?  [#permalink]

Show Tags

New post 11 Dec 2015, 19:11
A odd number is one that does not have 2 as its one of the prime factor

10! has a total of 8 factors of 2

So, we need to remove all these 8 factors to make the number odd

If we remove < 8 2 factors, the number will be even, and > 8 => number will not be an integer

Ans. D
Manager
Manager
User avatar
B
Joined: 01 Jan 2016
Posts: 53
GPA: 3.75
WE: Engineering (Energy and Utilities)
Re: If (10!)/(2y) is an odd integer, what is y?  [#permalink]

Show Tags

New post 26 Aug 2017, 08:44
The formula for finding the number of powers of a prime number p, in the n! is
n/p+n/p^2+n/p^3 ... till p^x≤n (https://gmatclub.com/forum/math-number- ... 88376.html)

Applying formula, p=2,n=10, x=3(since 2^3<10 but 2^4>10)
so, 10/2+10/4+10/8=5+2+1=8
So since 10! has 8 powers of 2, to make it odd, 2 in denominator needs to be raised to 8.
Option D
_________________

If you like it, give kudos. Thanks :)


The price of success is hard work, dedication to the job at hand, and the determination that whether we win or lose, we have applied the best of ourselves to the task at hand.
~Vince Lombardi
GMAT Club Bot
Re: If (10!)/(2y) is an odd integer, what is y?   [#permalink] 26 Aug 2017, 08:44
Display posts from previous: Sort by

If (10!)/(2y) is an odd integer, what is y?

  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®.