BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

At a dinner party 5 people are to be seated...

Expert replies
by BTGmoderatorLU » Fri Dec 01, 2017 1:49 pm
At a dinner party 5 people are to be seated around a circular table. Two sitting arrangements are considered different only when the positions of the people are different relative to each other. What is the total number of possible sitting arrangements or the group?

A. 5
B. 10
C. 24
D. 32
E. 120

The OA is C.

I'm confused with this PS question. Please, can any expert assist me with it? Thanks in advanced.
Join the discussion
Source: — Problem Solving |

by [email protected] » Fri Dec 01, 2017 4:18 pm
Hi LUANDATO,

We're told that 5 people are to be seated around a circular table and that two sitting arrangements are considered different only when the positions of the people are different relative to each other. We're asked for the total number of possible sitting arrangements of the group.

If the 5 people were sitting in a straight-line, then we'd be dealing with a standard Permutation question - and there would be 5! = 120 possible arrangements. Here, we're dealing with a circular table, so any of the 5 chairs could be the "first chair" and 1 arrangement of people could be created in 5 different ways. Thus, we have to divide 120 by 5 to determine the number of unique arrangements. 120/5 = 24 arrangements.

Final Answer: C

GMAT assassins aren't born, they're made,
Rich
Contact Rich at [email protected]
Image
Join the discussion

by GMATGuruNY » Sat Dec 02, 2017 3:24 am
To count circular arrangements:
1. Place someone in the circle.
2. Count the number of ways to arrange the REMAINING people.
LUANDATO wrote:At a dinner party 5 people are to be seated around a circular table. Two sitting arrangements are considered different only when the positions of the people are different relative to each other. What is the total number of possible sitting arrangements or the group?

A. 5
B. 10
C. 24
D. 32
E. 120
After one of the 5 people has been placed at the table, the number of ways to arrange the remaining 4 people = 4! = 24.

The correct answer is C.
Private tutor exclusively for the GMAT and GRE, with over 20 years of experience.
Followed here and elsewhere by over 1900 test-takers.
I have worked with students based in the US, Australia, Taiwan, China, Tajikistan, Kuwait, Saudi Arabia -- a long list of countries.
My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.

As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.

For more information, please email me (Mitch Hunt) at [email protected].
Student Review #1
Student Review #2
Student Review #3
Join the discussion

by Scott@TargetTestPrep » Thu Jan 11, 2018 2:14 pm
LUANDATO wrote:At a dinner party 5 people are to be seated around a circular table. Two sitting arrangements are considered different only when the positions of the people are different relative to each other. What is the total number of possible sitting arrangements or the group?

A. 5
B. 10
C. 24
D. 32
E. 120
When determining the number way to arrange a group around a circle we subtract one from the total and set it to a factorial. Thus, the total number of possible sitting arrangements for 5 people around a circular table is 4! = 24.

Answer: C

Scott Woodbury-Stewart
Founder and CEO
[email protected]

Image

See why Target Test Prep is rated 5 out of 5 stars on BEAT the GMAT. Read our reviews

ImageImage
Join the discussion