Friday 20 March 2015

PnC : Geometrical Arrangement


A peculiar set of questions sometimes appear in the MBA examinations wherein a set of distinct objects/people are arranged in some sort of geometrical positioning and we are looking for number of different arrangements.
So how do we go about them?..Let's unlock that door of mystery today.

Look at the first of the above set of images : A square.
Now if you position yourself in 8 of those spots, and imagine how your left,right and relative surroundings will look like, you should be able to realize that there are only 2 distinct orientations as denoted by distinct colors in the image. So we can place the first object in these 2 distinct orientations and simply arrange the remaining objects. Hence we get total arrangements as : 2*7! for the square.
Similarly if you now look at the other two images in the set, you should be able to achieve the following results :
Equilateral triangle : 3*8! and Rectangle : 5*9! by following the same logic.
Phase 1 of your learning is complete !
Let's proceed to phase 2 now : Extending the learning and gaining more perspective.
                                                                                                                                                                                            

Now here if you look to place yourself in the 8 possible spots you realize that they all are distinct orientations due to asymmetry of 2-same and 1-different side. Hence, the answer here will be : 8*7!
If you are with me till now, you should be able to reach the generalization found in several sources for a circular arrangement : 1*(n - 1)! or simply (n - 1)!.


Phase 2 complete !
Last and final phase of this topic comes down to a practice question which you should try and find the answer to. To confirm the answer look into comments but only when you have figured it out yourself. Else, I would advise you to go through the article again and find your way back here when you are ready.
Like,rate,share and let me know in comments how you found this article. I ll keep them coming to aid in your MBA journey ahead.

Cheers
!
AS

3 comments:

  1. I hope everyone reaches this point with comfort and find their answer to be : 9*8!
    Thanks for your time. Many more such articles to come. Keep following !

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  2. Replies
    1. Thanks for the feedback..Keep following for more :)

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