Water Measurement Flumes

In a stream of depth $d = 2.0\text{ m}$, velocities measured at $0.2 d$ and $0.8 d$ are $v_{0.2} = 1.2\text{ m/s}$ and $v_{0.8} = 0.8\text{ m/s}$. The average velocity $\bar{v} = (v_{0.2} + v_{0.8})/2$ in m/s is: