The total number of different combinations of one or more letters which can be made from the letters of the word ‘$MISSISSIPPI$’ is
$150$
$148$
$149$
None of these
A person wants to climb a $n-$ step staircase using one step or two steps. Let $C_n$ denotes the number of ways of climbing the $n-$ step staircase. Then $C_{18} + C_{19}$ equals
Total number of $3$ letter words that can be formed from the letters of the word $'SAHARANPUR'$ is equal to
The number of matrices of order $3 \times 3$, whose entries are either $0$ or $1$ and the sum of all the entries is a prime number, is$....$
Let $n(A) = 3, \,n(B) = 3$ (where $n(S)$ denotes number of elements in set $S$), then number of subsets of $(A \times B)$ having odd number of elements, is-
$\sum \limits_{ k =0}^6{ }^{51- k } C _3$ is equal to