permutation problem on GMAT Prep

[krishna239455]

Permutation problem. Seems to be difficult pls help.

[GMATGuruNY]

This question is about circular permutations.
VERY quick if we know the formula.
I posted an explanation here:

https://www.beatthegmat.com/gmat-prep-se ... 68201.html

[krishna239455]

thanks GuruNY for the formula

[Anurag@Gurome]

Permutation problem. Seems to be difficult pls help.

For circular seating arrangement, the number of arrangements of n distinct objects in a row is given by n!.
Number of arrangements of n distinct objects in a circle is given by (n - 1)!.

So, in this the total number of different possible seating arrangements for the group = (5 - 1)! = 4! = 4 * 3 * 2 * 1 = 24 ways

The correct answer is C.

[[email protected]]

The formula for circular seating arrangement is (n-1)! and so it comes down to 4! i.e 24 and the correct answer is C.

Hope this helps.

[[email protected]]

The funda or the logic behind the circular reasoning is very simple and can be compared to the linear arrangement. in a linear seating arrangement, the arraengements can be very different and the base is taken as the seat no. occupied by the individual.

But in a circular seating arrangement, the seat number can change because of the circular arrangement but the seating arrangement is based on the relative seating arrangement. So in circular seating arrangement you have to take 1 person among the people given as the base and so 1 person's probability of taking a seat is fixed. And the other people relative to that person's probability is considered...

This is extremely easy to understand when you have a diagram in front of you...

I hope this post helped...