In how many ways can a garland be made from exactly $10$ flowers?

In how many ways can $5$ keys be put in a ring?

Five persons $A, B, C, D$ and $E$ are seated in a circular arrangement. If each of them is given a hat of one of the three colours red,blue,and green,then the number of ways of distributing the hats such that the persons seated in adjacent seats get different coloured hats is

$20$ persons are invited for a party. In how many different ways can they and the host be seated at a circular table,if two particular persons are to be seated on either side of the host?

In how many ways can $5$ keys be arranged in a ring?

The number of ways of arranging all the letters of the word "$COMBINATIONS$" around a circle so that no two vowels come together is