Kinematics of motion in a straight line — practice question

The diagram presents a velocity-time graph that describes a car’s motion. It is made up of six straight-line sections. Starting from rest, the car speeds up to $20\,\text{m s}^{-1}$ in $5\,\text{s}$, and then continues at this speed for another $20\,\text{s}$. It next slows to $6\,\text{m s}^{-1}$ in $5\,\text{s}$. That speed is then kept for a further $(T - 30)\,\text{s}$. After that, the car speeds up again to $20\,\text{m s}^{-1}$ over $(50 - T)\,\text{s}$, before slowing to rest in $10\,\text{s}$.