A car covers AB distance with first one-third at velocity v_1 ms^-1, second one-third at v_2 ms^-1 and last one-third at v_3 ms^-1. If v_3=3 v_1,…

A car covers AB distance with first one-third at velocity $\displaystyle v_1 \mathrm{~ms}^{-1}$, second one-third at $\displaystyle v_2 \mathrm{~ms}^{-1}$ and last one-third at $\displaystyle v_3 \mathrm{~ms}^{-1}$. If $\displaystyle v_3=3 v_1, v_2=2 v_1$ and $\displaystyle v_1=11 \mathrm{~ms}^{-1}$ then the average velocity of the car is \_\_\_\_ $\displaystyle \mathrm{ms}^{-1}$.