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

 It is currently 23 Feb 2019, 05:15

### 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 February
PrevNext
SuMoTuWeThFrSa
272829303112
3456789
10111213141516
17181920212223
242526272812
Open Detailed Calendar
• ### Free GMAT RC Webinar

February 23, 2019

February 23, 2019

07:00 AM PST

09:00 AM PST

Learn reading strategies that can help even non-voracious reader to master GMAT RC. Saturday, February 23rd at 7 AM PT
• ### FREE Quant Workshop by e-GMAT!

February 24, 2019

February 24, 2019

07:00 AM PST

09:00 AM PST

Get personalized insights on how to achieve your Target Quant Score.

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

Author Message
TAGS:

### Hide Tags

Intern
Joined: 23 Sep 2011
Posts: 12
C(m,n) = (m!)/((m-n)!n!) for nonnegatives integers m and n, m>=n. If C  [#permalink]

### Show Tags

Updated on: 30 Oct 2016, 06:23
1
6
00:00

Difficulty:

5% (low)

Question Stats:

93% (01:33) correct 7% (02:03) wrong based on 140 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, 05:01.
Last edited by Bunuel on 30 Oct 2016, 06:23, edited 1 time in total.
Renamed the topic.
Manager
Joined: 28 Jun 2016
Posts: 207
Concentration: Operations, Entrepreneurship
Re: C(m,n) = (m!)/((m-n)!n!) for nonnegatives integers m and n, m>=n. If C  [#permalink]

### Show Tags

30 Oct 2016, 05:17
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
Joined: 16 Oct 2010
Posts: 8895
Location: Pune, India
Re: C(m,n) = (m!)/((m-n)!n!) for nonnegatives integers m and n, m>=n. If C  [#permalink]

### Show Tags

06 Dec 2017, 05:30
3
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

_________________

Karishma
Veritas Prep GMAT Instructor

Manager
Joined: 15 Feb 2018
Posts: 247
Re: C(m,n) = (m!)/((m-n)!n!) for nonnegatives integers m and n, m>=n. If C  [#permalink]

### Show Tags

19 Jan 2019, 16:08
Great question!
What is the question source?
Re: C(m,n) = (m!)/((m-n)!n!) for nonnegatives integers m and n, m>=n. If C   [#permalink] 19 Jan 2019, 16:08
Display posts from previous: Sort by

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

 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®.