Find all School-related info fast with the new School-Specific MBA Forum

 It is currently 27 Apr 2015, 14:37

### 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 June
Open Detailed Calendar

# 6 persons seat themselves at round table. What is the

Author Message
TAGS:
Manager
Joined: 25 Aug 2004
Posts: 171
Location: MONTREAL
Followers: 1

Kudos [?]: 11 [0], given: 0

6 persons seat themselves at round table. What is the [#permalink]  08 Jan 2005, 08:09
00:00

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 0 sessions
6 persons seat themselves at round table. What is the probability that 2 given persons are adjacent?

(A) 1/5
(B) 2/5
(C) 1/10
(D) 1/7
(E) 2/15
Current Student
Joined: 04 Jan 2005
Posts: 283
Location: Milan
Schools: Wharton, LBS, UChicago, Kellogg MMM (Donald Jacobs Scholarship), Stanford, HBS
Followers: 7

Kudos [?]: 138 [0], given: 3

I'd go with B (2/5).

Simply, given any position for person A, person B is adjacent to A if s/he sits in 2 out of 5 places left around the table.

P.
Manager
Joined: 17 Dec 2004
Posts: 62
Location: Find me if you can
Followers: 1

Kudos [?]: 0 [0], given: 0

Paradosso is right and the approach is simple.

One more approach which is not simple but holds many concepts is as follows...

A B C D E F be the six ppl and
A and B have to sit together.

Total # of ways n ppl can sit around a table is (n-1)!
therefore ppl can arrange themselves in (6-1)! equal to 5!
this becomes sample set.

Favourable events...
join two ppl so that they are one. That is they sit side by side.
Number of ways they can be arranged is 2. AB or BA ---1

Now these two ppl can be treated as one person. so this reduces # of ppl to 5.
AB C D E F
They can be arranged in (n-1)! ways that is (5-1)! ways. --2

Combining 1 and 2

2*4! is total number of favourable events

2/5.
_________________

Wish you all good luck
Bhimsen Joshi

Similar topics Replies Last post
Similar
Topics:
5 There are 6 people at a party sitting at a round table with 6 seats: A 14 08 Aug 2011, 12:00
5 Noble Knights are to be seated at a round table. In how 14 12 Jul 2007, 15:27
5 noble knights are to be seated around a round table. In 8 24 Mar 2007, 15:48
7 In how many ways can 6 people be seated at a round table if 10 15 Oct 2006, 08:32
13 persons take their places at a round table. What is teh 8 23 Jun 2006, 15:47
Display posts from previous: Sort by