Question

step by step explanation ​

Answer 1

$\: \: \boxed{\boxed{\sf{\mapsto \: Let \: us \: understand}}}$

$\mathsf\red{What \: is \: Average \: ?}$

$\mathsf{Formula \: :}\large\mathsf{\frac{sum \: of \: the \: observations}{The \: number \: of \: observations}}$

$\mathsf\red{Answer \: 4 \: :}$

The first 9 counting numbers : 1, 2 , 3, 4, 5, 6, 7, 8, 9

$\mathsf{Average \: :}\large\mathsf{\frac{sum \: of \: the \: observations}{The \: number \: of \: observations}}$

$\large\mathsf{= \: \frac{1+2+3+4+5+6+7+8+9}{9}}$

$\large\mathsf{= \: \frac{45}{9}}$

$\large\mathsf{= \: 5}$

$\mathsf\red{Answer \: 5 \: :}$

The odd numbers between 50 and 60 :- 51, 53, 55, 57, 59.

$\mathsf{Average \: :}\large\mathsf{\frac{sum \: of \: the \: observations}{The \: number \: of \: observations}}$

$\large\mathsf{= \: \frac{51+53+55+57+59}{5}}$

$\large\mathsf{= \: \frac{275}{5}}$

$\large\mathsf{= \: 55}$

$\mathsf\red{Answer \: 6 \: :}$

The even numbers between 7 and 17 :- 8, 10, 12, 14, 16

$\mathsf{Average \: :}\large\mathsf{\frac{sum \: of \: the \: observations}{The \: number \: of \: observations}}$

$\large\mathsf{= \: \frac{8+10+12+14+16}{5}}$

$\large\mathsf{= \: \frac{8+10+12+14+16}{5}}$

$\large\mathsf{= \: \frac{60}{5}}$

$\large\mathsf{= \: 12}$

$\mathsf\red{Answer \: 7 \: :}$

The prime numbers between 20 and 40 :- 23, 29, 31, 37

$\mathsf{Average \: :}\large\mathsf{\frac{sum \: of \: the \: observations}{The \: number \: of \: observations}}$

$\large\mathsf{= \: \frac{23+29+31+37}{4}}$

$\large\mathsf{= \: \frac{120}{4}}$

$\large\mathsf{= \: 30}$