$m$ men and $n$ women are to be seated in a row so that no two women sit together. If $m > n$, then the number of ways in which they can be seated is
$\frac{{m\;!\;(m + 1)\;!}}{{(m - n + 1)\;!}}$
$\frac{{m\;!\;(m - 1)\;!}}{{(m - n + 1)\;!}}$
$\frac{{(m - 1)\;!\;(m + 1)\;!}}{{(m - n + 1)\;!}}$
None of these
The value of $\sum \limits_{ r =0}^{20}{ }^{50- r } C _{6}$ is equal to
It is required to seat $5$ men and $4$ women in a row so that the women occupy the even places. How many such arrangements are possible?
A group of students comprises of $5$ boys and $n$ girls. If the number of ways, in which a team of $3$ students can randomly be selected from this group such that there is at least one boy and at least one girl in each team, is $1750$, then $n$ is equal to
Let $A = \left\{ {{a_1},\,{a_2},\,{a_3}.....} \right\}$ be a set containing $n$ elements. Two subsets $P$ and $Q$ of it is formed independently. The number of ways in which subsets can be formed such that $(P-Q)$ contains exactly $2$ elements, is
The number of triplets $(x, y, z)$. where $x, y, z$ are distinct non negative integers satisfying $x+y+z=15$, is