If the letters of the word $KRISNA$ are arranged in all possible ways and these words are written out as in a dictionary,then the rank of the word $KRISNA$ is

The number of integers greater than $6000$ that can be formed by using the digits $0, 5, 6, 7, 8,$ and $9$ without repetition is

The digits $4, 5, 6, 7, 8$ are written in every possible order. The number of numbers greater than $56000$ is

The total number of permutations of $n (> 1)$ different things taken not more than $r$ at a time,when each thing may be repeated any number of times is

Three persons enter a lift at the ground floor. The lift goes up to the $10^{\text{th}}$ floor. If the lift does not stop at the $1^{\text{st}}$,$2^{\text{nd}}$,and $3^{\text{rd}}$ floors,the number of ways in which the three persons can exit the lift at three different floors is equal to . . . . . . .

Evaluate $\frac{n!}{(n-r)!}$ when $n=6$ and $r=2$.