The number of circular permutation of 8 things taken 4 at a time is

The number of circular permutations of 8 things taken 4 at a time is

The number of circular permutations of 8 things taken 4 at a time is

The number of circular permutations of 8 things taken 4 at a time in both directions is

The number of circular permutations of 7 dissimilar things taken 5 at a time is

Number of circular permutations of 15 things taken 5 at a time in one direction is

Find the number of permutations of 8 things, taken 3 at a time, in which 2 particular things are always : included .

Find the number of permutations of 8 things, taken 3 at a time, in which 2 particular things are always : excluded .

The number of permutations of n things taken r at a time if 3 particular things always occur is

The number of permutations of n things taken r at a time if 3 particular things always occur is