$A$ car travels the first half of a distance between two places at a speed of $30 \, km/hr$ and the second half of the distance at $50 \, km/hr$. The average speed of the car for the whole journey is .......... $km/hr$.

$A$ train has a speed of $60\, km/h$ for the first one hour and $40\, km/h$ for the next half hour. Its average speed in $km/h$ is

Write the relation between speed and the magnitude of velocity.

$A$ 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 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 $m/s$)

$A$ body covers half of its distance with speed $u$ and the other half with a speed $v$,the average speed of the body is