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