Here's the problem, While Traveling through the first half of the distance of the trip, your average velocity is 14.0 m/s. What average velocity would you need during the second half of the distance on your trip, if you wanted your average velocity for the entire trip to be 24.0 m/s. Here's what I did. I used the formula V_av = 1/2(v_o+v). I plugged in 24.0 m/s into V_av and plugged in 14.0 m/s into V_o. I solved from there and got 34.0 m/s. That isn't the right answer. Did I use the right formula? Is there a way to express the time for the first and second half of the trip?