A runner dashes from the starting line (x=0) to a point 108 m away and then turns around and runs to a point 19 m away from the starting point in 23.4 seconds. To the nearest tenth of a m/s what is the average speed?

total distance: 108 + 89 = 197m

so, avg speed is 197m/23.4s = 8.4m/s

assuming he stopped 19m short of the starting line, and not 19m past it!