20 were invited for a party, find the no ways in which 20 persons and the host can be seated around a circular table such that two particular person be seated on either side of host.
Since the place of host is fixed and the 2 particular person around him is fixed. Treating 2 person and 1 host as single unit.
No of ways = $(19 - 1)! * 2$ , but the solution does not match the answer provided with textbook.