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 persons be seated at a round table so that 2 particular persons sit together?

In how many ways can 8 persons be seated at a round table so that all shall not have the same neighbours in any two arrangements?

In how many ways can 6 persons can be seated at a round table so that all shall not have the same neighbours in any two arrangements?

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

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

In how many ways can 12 members be seated at a round table when the secretary and the joint secretary are always the neighbours of the president.