$A$ train travels from city-$A$ to city-$B$ with a constant speed of $18 \,ms^{-1}$ and returns back to city-$A$ with a constant speed of $36 \,ms^{-1}$. Find its average speed during the journey. (in $\,ms^{-1}$)

$A$ particle moving in a straight line covers half the distance with a speed of $3 \, m/s$. The other half of the distance is covered in two equal time intervals with speeds of $4.5 \, m/s$ and $7.5 \, m/s$ respectively. The average speed of the particle during this motion is...... $\, m/s$

The velocity of an object moving in a straight line path is given as a function of time by $v = 6t - 3t^2$,where $v$ is in $m/s$ and $t$ is in $s$. The average velocity of the object between $t = 0$ and $t = 2 \ s$ is

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

$A$ car covers $2/5^{th}$ of the total distance with speed $v_1$ and $3/5^{th}$ of the total distance with speed $v_2$. What is its average speed?

$A$ person travels $x$ distance with velocity $v_1$ and then $x$ distance with velocity $v_2$ in the same direction. The average velocity of the person is $v$. Then the relation between $v, v_1$ and $v_2$ will be: