There are 9 chairs in a room on which 6 persons are to be seated, out of which one is guest with one specific chair. In how many ways they can sit

There are 9 chairs in a room on which 6 persons are to be seated, out of which one is a guest with one specific chair. In how many ways can they sit

There persons enter into a conference hall in which there are 10 seats. In how many ways they can take their seats ?

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

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