Which among average speed and average velocity can be positive,negative or zero?

$A$ particle covers half of its total distance with speed $v_1$ and the rest half distance with speed $v_2$. Its average speed during the complete journey is

$A$ person goes from point $P$ to point $Q$ covering $1/3$ of the distance with speed $10 \, km/h$,the next $1/3$ of the distance at $20 \, km/h$,and the last $1/3$ of the distance at $60 \, km/h$. The average speed of the person is ............ $km/h$.

Velocity of an object in rectilinear motion is given as a function of time by $v = t - t^3$,where $v$ is in $m/s$ and $t$ is in seconds. Its average velocity over the time interval from $t = 0 \ s$ to $t = 2 \ s$ is ........ $m/s$.

Explain average velocity and average speed.

The displacement $(x)$ and time $(t)$ graph of a particle moving along a straight line is shown in the figure. The average velocity of the particle in the time of $10 \ s$ is (in $m \ s^{-1}$)