a person starts at a postion of 25 meters and finishes at a position of 2 meters. the trip takes 4.5 seconds. what is the person's average velocity? what is the person's average speed?

Aperson walks first at a constant speed of 4.89 m/s along a straight line from point a to point b and then back along the line from b to a at a constant speed of 2.95 m/s. what is the average speed over the entire trip?