[填空题]
A person jogs eight complete laps around a q5d/k8shm:z9d1oe ijcc/z k z44gh)z uuart;9q8whtu *78qcy sc- zrkxe )ier-mile ($1 \; mile = 1609 \; m$) track in a total time of 20.0 min. Calculate (a) the average speed $m/s$ and (b) the average velocity $m/s$