Find the number of ways in which 16 constables can be assigned to patrol villages, 2 for each.

Answer

`(16!)/((2!)^(8))`

Explanation

The number of ways 16 constables can be divided into 8 bactes is `(16)!//8!(2!)^(8)`.
Now, the first batch may be assigned to patrol any of the 8 batches to patrol 8 villages is
`((16)!)/(8!(2!)^(8))(8!)=((16)!)/((2!)^(8))`