Average velocity = \(\frac{total speed}{total time}\) Total distance = Area under the graph i.e area of trapezium = \(\frac{1}{2}\)(a + b) x h = 0.5(6 + 10) x 10 = 80m Total time = 10secs Average velocity = \(\frac{total speed}{total time}\) = \(\frac{80}{10}\) = 8m/s so closest answer is 8.5m/s