[30 pts] Alex is biking from home (at point A) to drop off a letter at the post office (at point B) along a straight path. The post office is located east of Alex's house. He starts with a speed of 3 m/s for 10 minutes. Stop for 5 minutes to answer a phone call then turn back to pick up another letter at his friend's house (at point C) then continue to the post office. The velocity-time graph of Alex's trip is plotted below. The speed (v) is in meter per second (m/s) and the time (t) in minutes (min). Alex's arrives post office at a speed of 6 m/s. un A A N v (m/s) O 10 15 20 C 30 35 40 bw N t (min) [Answer in 2 significant figures] a) (15 pts) Where is Alex friend's house relative to Alex's home (i.e. how far away and is it east or west of Alex's home?) b) (7 pts) If Alex wants to go back home in 5 minutes, how fast does he need to bike back? c) (8 pts) What is his average speed and average velocity of his whole trip