$A$ body moves in a straight line with speeds $v_1$ and $v_2$ for distances which are in the ratio $1: 2$. Find the average speed.

$A$ car travels $\frac{1}{3}$ of the total distance on a straight road at a speed of $20 \, km/hr$ and the remaining distance at a speed of $60 \, km/hr$. What is the average speed of the car in $km/hr$?

The position of an object moving along the $x$-axis is given by $x = a + b t^2$,where $a = 8.5 \; m$,$b = 2.5 \; m s^{-2}$,and $t$ is measured in seconds. What is the average velocity between $t = 2.0 \; s$ and $t = 4.0 \; s$ (in $; m s^{-1}$)?

"The magnitude of average velocity is equal to average speed". This statement is not always correct and not always incorrect. Explain with an example.

$A$ man walks on a straight road from his home to a market $2.5 \,km$ away with a speed of $5 \,km/h$. Finding the market closed,he instantly turns and walks back home with a speed of $7.5 \,km/h$. The average speed of the man over the interval of time $0$ to $40 \,min$ is equal to

$A$ car moves from $X$ to $Y$ with a uniform speed $v_1$ and returns from $Y$ to $X$ with a uniform speed $v_2$. The average speed for this round trip is