The number of all four-digit numbers which do not have four distinct digits is

$A$ set contains $2n + 1$ elements. The number of subsets of this set containing more than $n$ elements is equal to

The number of different words that can be formed from the letters of the word $SUCCESS$ in which the two $C$ are together but no two $S$ are together are:

If $8 \cdot {}^{7}P_{r} = 7 \cdot {}^{8}P_{r-1}$,what is the value of $r$?

All the letters of the word $TABLE$ are permuted and the strings of letters (may or may not have meaning) thus formed are arranged in dictionary order. Then the rank of the word $TABLE$ counted from the rank of the word $BLATE$ is

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