Permutation Examples (Tutorial)
and Basics in counting

Question

Permutation Examples (Tutorial)
and Basics in counting

arindameducationusc · Answer

$\Huge\color{red}{Fundamental~rule~of} $
$\Huge\color{Blue}{Multiplication} $


If we take two identical jobs in which one can be completed in 'm' no. of ways & other can be completed in 'n' no. of ways. And the tasks is completed when both the jobs are completed then the total no. f way completing the task is given by
$$m*n$$

$\Huge\color{Red}{Fundamental~rule~of} $
$\Huge\color{Blue}{Addition} $

If we have two jobs in which one can be completed in 'm' no. of ways & the other can be completed in 'n' no. of ways. And the task is completed when any one of the jobs is completed then the total no. of way of completing the task is given by 
$$m+n$$

arindameducationusc · Answer

$\Large\color{red}{Q} $ In a class there are 10 boys & 8 girls. A teacher wants to select a boy $\Large\color{red}{and} $ a girl to represent the class in a function. In how many ways the selection can be done?

$\Large\color{Blue}{Ans} $
Total no. of way = 10*8=80

arindameducationusc · Answer

$\Large\color{red}{Q} $ In a class there are 10 boys & 8 girls. A teacher wants to select a boy $\Large\color{red}{Or} $ a girl to represent the class in a function. In how many ways the selection can be done?

$\Large\color{Blue}{Ans} $
Total no. of way = 10+8=18ways

arindameducationusc · Answer

$\Large\color{red}{Q} $ There are 3 stations A,B,C. 5 routes are going from A to B and 4 routes are going from B to C. Find the number of ways in which a person can go A to C via B.

$\Large\color{Blue}{Ans} $

|dw:1440311727639:dw|

Number of ways=5*4=20

arindameducationusc · Answer

$\Large\color{red}{Q} $ A room has 6 doors. In how many ways a man can enter through one door and come out through a different door.

$\Large\color{Blue}{Ans} $
|dw:1440312250191:dw|
No. of ways =6*5=30