The number of four-letter words that can be formed with letters $a, b, c$ such that all three letters occur is
$30$
$36$
$81$
$256$
Determine the number of $5$ card combinations out of a deck of $52$ cards if there is exactly one ace in each combination.
From a class of $25$ students, $10$ are to be chosen for an excursion party. There are $3$ students who decide that either all of them will join or none of them will join. In how many ways can the excursion party be chosen?
In an examination, a question paper consists of $12$ questions divided into two parts i.e., Part $\mathrm{I}$ and Part $\mathrm{II}$, containing $5$ and $7$ questions, respectively. A student is required to attempt $8$ questions in all, selecting at least $3$ from each part. In how many ways can a student select the questions?
Let $S=\{1,2,3, \ldots ., 9\}$. For $k=1,2, \ldots \ldots, 5$, let $N_K$ be the number of subsets of $S$, each containing five elements out of which exactly $k$ are odd. Then $N_1+N_2+N_3+N_4+N_5=$
What is the number of ways of choosing $4$ cards from a pack of $52$ playing cards? In how many of these
four cards are of the same suit,