Driving at 40 km/h for 2 h contributes a distance of 80 km, while driving at 55 km/h for 2h contributes 110 km, giving a total of 190 km traveled. If the car is traveling in the same direction throughout this ordeal, then the average velocity is
[tex]\bar v=\dfrac{190\,\mathrm{km}}{4\,\mathrm h}=47.5\,\dfrac{\mathrm{km}}{\mathrm h}[/tex]
