Find the arithmetic mean between:

(i) 9 and 19

To find: Arithmetic mean between 9 and 19

The formula used: Arithmetic mean between a and $\mathrm{b}=\frac{a+b}{2}$

We have 9 and 19

A.M. $=\frac{9+19}{2}$

$=\frac{28}{2}$

$=14$

(ii) 15 and -7

To find: Arithmetic mean between 15 and -7

The formula used: Arithmetic mean between a and $\mathrm{b}=\frac{a+b}{2}$

We have 15 and -7

A.M. $=\frac{(15)+(-7)}{2}$

$=\frac{15-7}{2}$

$=\frac{8}{2}$

$=4$

(iii) -16 and -8

To find: Arithmetic mean between -16 and -8

The formula used: Arithmetic mean between $=\mathrm{a}$ and $\mathrm{b}=\frac{a+b}{2}$

We have -16 and -8

A.M. $=\frac{(-16)+(-8)}{2}$

$=\frac{-16-8}{2}$

$=\frac{-24}{2}$

$=-12$