Question

Ex 3 : Find the number of ways in which
12 different flowers can be arranged in a garland
so that 4 particular flowers are always together.

Answer 1

flowers which are always together can be considered as one SET,

Therefore we have to arrange one SET ( 4 flowers ) and 4 other flowers into a garland.

Which means, 5 things to be arranged in a garland.

(5-1)!

And the SET of flowers can arrange themselves within each otherin 4! ways.

Therefore

(5-1)!*(4!)

But, Garland, looked from front or behind does not matter. Therefore the clockwise and anti clockwise observation does not make difference.

Therefore

(5-1)! * (4!)/ 2

=288

... i didnt stole this answer from somewhere lol :)