$A$ 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 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

$A$ 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 $\,ms^{-1}$)

$A$ car covers distance $AB$ with the first one-third at velocity $v_{1} \, ms^{-1}$,the second one-third at $v_{2} \, ms^{-1}$,and the last one-third at $v_{3} \, ms^{-1}$. If $v_{3}=3v_{1}$,$v_{2}=2v_{1}$,and $v_{1}=11 \, ms^{-1}$,then the average velocity of the car is . . . . . . $ms^{-1}$.

$A$ particle travels half of the distance of a straight journey with a speed $6 \,m/s$. The remaining part of the distance is covered with speed $2 \,m/s$ for half of the time of the remaining journey and with speed $4 \,m/s$ for the other half of the time. The average speed of the particle is ....... $m/s$.

$A$ car starts from rest and moves such that it possesses average speeds of $5 \, ms^{-1}$,$10 \, ms^{-1}$,and $15 \, ms^{-1}$ in the first,second,and third seconds,respectively. What is the total distance covered by the car in these three seconds? ......... $m$