Finding the number of ways in which ten things, of which 4 are alike, can be arranged in a circular order.

Things which are addictive.

Find the number of ways in which 12 different flowers can be arranged in a garland so that 4 particular flowers are never seperate.

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

Find the number of ways in which 7 persons can be arranged at a round table, if two particular persons may not sit together.

Find the number of ways in which 5 red and 4 white balls can be drawn from a bag containing 10 red and 8 white balls.

The number of ways in which 7 distinct objects can be distributed among 4 children is

The number of ways in which we can post 5 letters in 10 letter boxes is

The number of ways in which n books can be arranged on a shelf so that two particular books are not together is