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

Show that the number of ways in which n books may be arranged on a shelf so that two particular books shall not be together is (n-2)(n-1)!

Let N denote the number of ways in which n boys can be arranged in a line so that 3 particular boys are seperated then N is equal to

The number of ways in which 6 men can be arranged in a row so that the particular 3men sit together,is:

The number of ways in which 10 books can be arranged in a row such that two specified books are side by side is

Number of ways in which 15 different books can be arraged on a shelf so that two particular books shall not be together is

The number of ways in which seven persons can be arranged at a round table if two particular persons may not sit together, is