Answer
$v_{avg}=1.47m/s$
Work Step by Step
Average velocity is defined as $$v_{avg}=\frac{\Delta x}{\Delta t}$$ The man stands still for five minutes, so his displacement is zero for that period. He walks at 2.20m/s for four minutes (from 5-9min.), which is 4(60s)=240 seconds. Solving the formula for displacement yields $$\Delta x = v\Delta t$$ Substituting known values of $v=2.20m/s$ and $\Delta t=240s$ yields $$\Delta x = (2.20m/s)(240s)=528m$$ Substituting this displacement $\Delta x=528m$ and $\Delta t=6.00min=6(60s)=360s$ (total time traveled) yields an average velocity of $$v_{avg}=\frac{528m}{360s}=1.47m/s$$
