The position $(x)$-time $(t)$ graph for a particle moving along a straight line is shown in the figure. The average speed of the particle in the time interval $t=0$ to $t=8 \, s$ is .......... $m/s$.

$A$ body travelling along a straight line path travels the first half of the distance with a velocity of $7 \,m/s$. During the travel time of the second half of the distance, the first half of the time is travelled with a velocity of $14 \,m/s$ and the second half of the time is travelled with a velocity of $21 \,m/s$. Then the average velocity of the body during the entire journey is: (in $\,m/s$)

$A$ particle moves for $20 \,s$ with velocity $3 \,m/s$,then with velocity $4 \,m/s$ for another $20 \,s$,and finally with velocity $5 \,m/s$ for the next $20 \,s$. What is the average velocity of the particle in $m/s$?

$A$ vehicle travels half the distance with speed $v$ and the remaining distance with speed $2v$. Its average speed is:

$A$ 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 ....... $m/s$.

$A$ body has speeds $V$,$2V$,and $3V$ in the first $1/3$ of distance $S$,the second $1/3$ of distance $S$,and the third $1/3$ of distance $S$ respectively. Its average speed will be: