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

 It is currently 22 Apr 2019, 23:12

### 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

# Eight persons in an organization including A and B

Author Message
TAGS:

### Hide Tags

Intern
Joined: 18 Jul 2014
Posts: 7
Eight persons in an organization including A and B  [#permalink]

### Show Tags

16 Jan 2016, 23:41
7
00:00

Difficulty:

45% (medium)

Question Stats:

64% (02:23) correct 36% (02:18) wrong based on 90 sessions

### HideShow timer Statistics

Eight persons in an organization including A and B were to be divided in two groups of 4 members each. The total number of groups containing both A and B is what fraction of the total number of groups which can be formed?

1/4
1/70
3/14
1/10
11/14
Math Expert
Joined: 02 Aug 2009
Posts: 7578
Re: Eight persons in an organization including A and B  [#permalink]

### Show Tags

17 Jan 2016, 00:10
1
jyotibrata wrote:
Eight persons in an organization including A and B were to be divided in two groups of 4 members each. The total number of groups containing both A and B is what fraction of the total number of groups which can be formed?

1/4
1/70
3/14
1/10
11/14

The fraction is nothing but the probability..

Number to choose 4 out of 8= 8C4..
Number to choose A and B and 2 from remaining 6=6C2..
prob of A and B choosen=6C2/8C4= {6!/4!2!}/{8!/4!4!}..
6!4!4!/8!4!2!=3/2*7=3/14
C
_________________
Intern
Joined: 10 Feb 2016
Posts: 3
GMAT 1: 670 Q42 V40
GMAT 2: 750 Q49 V42
GPA: 3.59
Re: Eight persons in an organization including A and B  [#permalink]

### Show Tags

20 Apr 2016, 04:55
This question is not a DS question so why is it tagged as 'DS'
Manager
Joined: 12 Jun 2015
Posts: 79
Re: Eight persons in an organization including A and B  [#permalink]

### Show Tags

20 Apr 2016, 17:10
The 8 people need to be divided in 2 (similar) groups of 4 each. So the ordering of the groups will not matter here.
This can be achieved in 8C4 ways= 8! / (4! * 4!)

The number of groups that contain both A and B will be 6C4 (4 in one group , and 2 in the group with A and B)= 6!/ (4! * 2!)

The Fraction asked = 6!/ (4! * 2!) / 8! / (4! * 4!)
= 3/14

Correct Option : C
Non-Human User
Joined: 09 Sep 2013
Posts: 10599
Re: Eight persons in an organization including A and B  [#permalink]

### Show Tags

22 Jul 2017, 13:36
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________
Re: Eight persons in an organization including A and B   [#permalink] 22 Jul 2017, 13:36
Display posts from previous: Sort by

# Eight persons in an organization including A and B

 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®.