In how many ways, `20` guests and `1` host can be arranged around a circular table so that two particular guests are on either side of the host?

A host invites 20 persons for a party. The number of ways they can be seated at a circular table such that two particular persons be seated on either side of the host is

12 persons are invited for a party. In how many different ways can they and the host be seated at a circular table, if two particular persons are to be seated on either side of the host?

20 persons were Invited for party . In how many ways can they and the host be seated around a circular table? In how many of these ways will two particular persons be seated on either side of the host?

In how many ways can 7 people be arranged at round table, so that two particular persons be together?

In how many ways 10 boys and 5 girls can sit around a circular table so that no two girls sit together.

If 20 persons were invited for a party, in how many ways can they and the host be seated at a circular table? In how many of these ways will two particular persons be seated on either side of the host?