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 $?$
since, the team has to consist of at least $3$ girls, the team can consist of
$(a)$ $3$ girls and $2$ boys, or
$(b)$ $4$ girls and $1$ boy.
Note that the team cannot have all $5$ girls, because, the group has only $4$ girls.
$3$ girls and $2$ boys can be selected in $^{4} C _{3} \times^{7} C _{2}$ ways.
$4$ girls and $1$ boy can be selected in $^{4} C _{4} \times^{7} C _{1}$ ways.
Therefore, the required number of ways
$=\,^{4} C _{3} \times^{7} C _{2}+^{4} C _{4} \times^{7} C _{1}=84+7=91$
Two packs of $52$ cards are shuffled together. The number of ways in which a man can be dealt $26$ cards so that he does not get two cards of the same suit and same denomination is
$^n{C_r}{ + ^n}{C_{r - 1}}$ is equal to
Determine $n$ if
$^{2 n} C_{3}:\,^{n} C_{3}=12: 1$
In an examination of Mathematics paper, there are $20$ questions of equal marks and the question paper is divided into three sections : $\mathrm{A}, \mathrm{B}$ and $\mathrm{C}$. A student is required to attempt total $15$ questions taking at least $4$ questions from each section. If section $A$ has $8$questions, section $\mathrm{B}$ has $6$ questions and section $\mathrm{C}$ has $6$ questions, then the total number of ways a student can select $15$ questions is
A father with $8$ children takes them $3$ at a time to the Zoological gardens, as often as he can without taking the same $3$ children together more than once. The number of times each child will go to the garden is