A round table conference is to be held between 20 delegates of 20 countries. In how many ways can they be seated if two particular delegates are always together.

A round table conference is to be held between delegates of 20 countries. In how many ways can they be seated if two particular delegates are never together?

A round-table conference is to be held among 20 delegates belonging from 20 different countries. In how many ways can they be seated if two particular delegates are (i) always to sit together, (ii) never to sit together .

A round-table conference is to be held among 20 delegates belonging from 20 different countries. In how many ways can they be seated if two particular delegates are (i) always to sit together, (ii) never to sit together .

A round table coference is to be held between 20 delegates. How many seating arrangements are possible if two particular delegates are always to sit together .

In how many ways can 6 persons be seated at a round table?

In how many ways can 5 persons be seated at a round table?

In how many ways can 8 boys be seated at a round table?

In how many ways can 12 books be arranged on a shelf if 4 particular books must always be together.

In how many ways can 3 people be seated in a row containing 7 seats?

In how many ways can 20 persons be seated round a table if there are 9 chairs.