A horse is capable of moving at four different speeds: walk (1.9 m/s), trot (5.0 m/s), canter (7.0 m/s), and gallop (12 m/s). An is learning how to ride a horse. She spends 15 minutes riding at a walk and 1.8 minutes at each other speed. If she traveled the whole way in the positive direction, what was her average velocity over the trip?