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

It is currently 19 Aug 2018, 00:39

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

C(m,n) = (m!)/((m-n)!n!) for nonnegatives integers m and n, m>=n. If C

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

Hide Tags

Intern
Intern
User avatar
Joined: 23 Sep 2011
Posts: 17
GMAT ToolKit User Reviews Badge
C(m,n) = (m!)/((m-n)!n!) for nonnegatives integers m and n, m>=n. If C  [#permalink]

Show Tags

New post Updated on: 30 Oct 2016, 07:23
5
00:00
A
B
C
D
E

Difficulty:

  5% (low)

Question Stats:

85% (01:00) correct 15% (00:26) wrong based on 103 sessions

HideShow timer Statistics

C(m,n) = (m!)/((m-n)!n!) for nonnegatives integers m and n, m>=n. If C(5,3)=C(5,x) and x≠3, what is the value of x?


(A) 0
(B) 1
(C) 2
(D) 4
(E) 5

Originally posted by interceptor77 on 30 Oct 2016, 06:01.
Last edited by Bunuel on 30 Oct 2016, 07:23, edited 1 time in total.
Renamed the topic.
Manager
Manager
avatar
Joined: 28 Jun 2016
Posts: 207
Location: Canada
Concentration: Operations, Entrepreneurship
Re: C(m,n) = (m!)/((m-n)!n!) for nonnegatives integers m and n, m>=n. If C  [#permalink]

Show Tags

New post 30 Oct 2016, 06:17
1
interceptor77 wrote:
C(m,n) = (m!)/ ((m-n)!n!) for nonnegatives integers m and n, m>=n. If C(5,3)=C(5,x) and x≠3, what is the value of x?


(A) 0
(B) 1
(C) 2
(D) 4
(E) 5


In Combinatorics,

nCr = nC(n-r)

So x = 5-3 =2

C


Sent from my iPhone using GMAT Club Forum mobile app
Veritas Prep GMAT Instructor
User avatar
P
Joined: 16 Oct 2010
Posts: 8195
Location: Pune, India
Re: C(m,n) = (m!)/((m-n)!n!) for nonnegatives integers m and n, m>=n. If C  [#permalink]

Show Tags

New post 06 Dec 2017, 06:30
2
interceptor77 wrote:
C(m,n) = (m!)/((m-n)!n!) for nonnegatives integers m and n, m>=n. If C(5,3)=C(5,x) and x≠3, what is the value of x?


(A) 0
(B) 1
(C) 2
(D) 4
(E) 5


The given expression should remind you that it is mCn i.e. selecting n out of total m items.

We know that mCn = mC(m-n) and hence 5C3 = 5C(5-3) = 5C2

Even if this doesn't strike you during the exam, simply substitute.

(m!)/((m-n)!n!) = 5!/3!*2! = 5!/(5-x)!*x!

(5-x)!*x! = 3!*2!

We see that x = 2

Answer (C)
_________________

Karishma
Veritas Prep GMAT Instructor

Save up to $1,000 on GMAT prep through 8/20! Learn more here >

GMAT self-study has never been more personalized or more fun. Try ORION Free!

Re: C(m,n) = (m!)/((m-n)!n!) for nonnegatives integers m and n, m>=n. If C &nbs [#permalink] 06 Dec 2017, 06:30
Display posts from previous: Sort by

C(m,n) = (m!)/((m-n)!n!) for nonnegatives integers m and n, m>=n. If C

  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®.