A runner dashes from the starting line (x = 0) to a point 84 m away and then turns around and runs to a point 37 m away from the starting point in 30 seconds. To the nearest tenth of a m/s what is the average speed?
distance travelled = 84m + (84-37)m
= 84m + 47m
distance travelled = 131m
time = 30 seconds
average speed = distance travelled / time
= 131m / 30s
= 4.366666667 m/s
~= 4.4 m/s