PS - Permutations Q

This topic has expert replies
Master | Next Rank: 500 Posts
Posts: 118
Joined: Wed Mar 16, 2011 1:44 pm
Location: Canada
Followed by:2 members
GMAT Score:530

PS - Permutations Q

by ccassel » Fri Jul 29, 2011 8:23 am
Hi,

How would the solution to this question differ if it were "row" vs. "circular"?

4 people are to be seated around a circular table at a banquet. If there are exactly 4 places around the table where the people are to be seated, in how many different orders may they be arranged?

A. 4
B. 6
C. 12
D. 24
E. 64

[spoiler]OA 24 or 6?[/spoiler]

Cheers,
Source: — Problem Solving |

Legendary Member
Posts: 1084
Joined: Fri Apr 15, 2011 2:33 pm
Thanked: 158 times
Followed by:21 members

by pemdas » Fri Jul 29, 2011 9:34 am
4!/4 would be answer or 6 B
in row question this would be 4! or 24

consider four people ABCD in a row, then the following combination sets would be different
ABCD
DABC
CDAB
BCDA, in total four sets are different
However in circular permutation we have the above listed combination sets being the same, as the order around the circle makes them similar relative to each other

So in a row combination we have four different arrangements that result in the same arrangement in circular permutation
ccassel wrote:Hi,

How would the solution to this question differ if it were "row" vs. "circular"?

4 people are to be seated around a circular table at a banquet. If there are exactly 4 places around the table where the people are to be seated, in how many different orders may they be arranged?

A. 4
B. 6
C. 12
D. 24
E. 64

[spoiler]OA 24 or 6?[/spoiler]

Cheers,
Success doesn't come overnight!