A group of $9$ students, $s 1, s 2, \ldots, s 9$, is to be divided to form three teams $X, Y$ and, $Z$ of sizes $2,3$ , and $4$, respectively. Suppose that $s_1$ cannot be selected for the team $X$, and $s_2$ cannot be selected for the team $Y$. Then the number of ways to form such teams, is. . . .
$660$
$661$
$664$
$665$
A set contains $(2n + 1)$ elements. The number of sub-sets of the set which contains at most $n$ elements is :-
If $n = ^mC_2,$ then the value of $^n{C_2}$ is given by
A group consists of $4$ girls and $7$ boys. In how many ways can a team of $5$ members be selected if the team has at least $3$ girls $?$
If $^n{P_r}$=$ 720$.$^n{C_r},$ then $r$ is equal to
Statement$-1:$ The number of ways of distributing $10$ identical balls in $4$ distinct boxes such that no box is empty is $^9C_3 .$
Statement$-2:$ The number of ways of choosing any $3$ places from $9$ different places is $^9C_3 $.