Mary starts from her house, walks 80 meters south, and stops to chat with her aunt on the sidewalk. after chatting for a few minutes, she walks 125 meters to the west to meet a friend and then walks 45 meters north with her friend to a cafe for lunch. overall, she takes 10 minutes to do all this. what is mary’s average speed? select one of the options below as your a. 8 meters/second b. 1.25 meters/second c. 25 meters/second d. 4.5 meters/second e. 0.42 meters/second