How many words can be made from the letters of the word $DELHI$,if $L$ comes in the middle in every word?

In how many ways can $5$ boys and $5$ girls sit in a circle so that no two boys sit together?

There are $5$ apples,$4$ mangoes,$3$ oranges,and $1$ each of $2$ other varieties of fruits. The number of ways of selecting at least one fruit of each kind is

$3$ boys and $3$ girls are to be seated around a circular table. Among the boys,$X$ does not want any girl as a neighbour,and among the girls,$Y$ does not want any boy as a neighbour. How many such arrangements are possible?

The number of $5$ digit telephone numbers having at least one of their digits repeated is

There are $16$ points in a plane,no three of which are in a straight line except $8$ which are all in a straight line. The number of triangles that can be formed by joining them equals