Is the average of different speeds called average speed? Do you agree?

$A$ car moves a distance of $200 \; m$. It covers the first half of the distance at a speed of $40 \; km/h$ and the second half of the distance at a speed of $v$. If the average speed is $48 \; km/h$,the value of $v$ is: (in $; km/h$)

$A$ person walks along a straight road from his house to a market $2.5 \,km$ away with a speed of $5 \,km/h$ and instantly turns back and reaches his house with a speed of $7.5 \,km/h$. The average speed of the person during the time interval $0$ to $50 \,min$ is (in $m/s$)

$A$ car travels from $A$ to $B$ at a speed of $20\,km/hr$ and returns at a speed of $30\,km/hr$. The average speed of the car for the whole journey is............$km/hr$

$A$ biker travels $\frac{1}{3}$ of the distance $L$ with speed $v_1$ and $\frac{2}{3}$ of the distance with speed $v_2$. Then the average speed is

$A$ motorcyclist travels a certain distance with a uniform speed of $30\, m/s$ and immediately turns back and returns to the starting point with a uniform speed of $20\, m/s$. Then the average speed of the motorcycle is ..........$m/s$ :-