Q.

In a hotel, four rooms are available. Six persons are to be accommodated in these four rooms in such a way that each of these rooms contains at least one person and at most two persons. Then the number of all possible ways in which this can be done is ______.                   [2020]


Ans.

(1080)

Groups can be possible in only 2, 2, 1, 1 way.

Number of ways of dividing persons in group

=6!(2!)2(1!)2(2!)2

Number of ways after arranging rooms =6!(2!)4·4!=1080