posted by Andres .
Larry leaves home at 1:01 and runs at a constant speed to the lamppost. He reaches the lamppost at 1:10, immediately turns, and runs to the tree. Larry arrives at the tree at 1:26. What is Larry's average velocity during his trip from home to the lamppost, if the lamppost is 346.0 m west of home, and the tree is 640.0 m east of home?
d = 2 * 346 + 640 = 1332 m,
t = 1:26 - 1:1 = 25 min,
v = d/t = 1332 m / 25 min = 53.3 m/min.