Kinematics of motion in a straight line — practice question

For a particle travelling along a straight line, its velocity is $v\,\text{m s}^{-1}$ at $t$ seconds after it leaves the fixed point $O$. The diagram displays a velocity-time graph that represents the particle's motion for $t=0$ to $t=16$. It is made up of five straight line sections. The acceleration from $t=0$ to $t=3$ is $3\,\text{m s}^{-2}$. At $t=5$, the particle's velocity is $7\,\text{m s}^{-1}$ and it is momentarily at rest at $t=8$. It then is at rest again at $t=16$. The smallest velocity reached is $V\,\text{m s}^{-1}$.