Question

Solving Story Problems Involving Slope
A 2-column table with 3 rows. Column 1 is labeled time elapsed (hours) with entries 2, 4, 7. Column 2 is labeled Distance Run (miles) with entries 13.5, 27.5, 48.5.

Larry recorded his time as he ran. What was his average speed from hour 2 to hour 4?



What was his average speed from hour 4 to hour 7?



Did he speed up or slow down?

Answer 1

Average speed = change in distance / change in time.

From hour 2 to hour 4:
Δdistance = 27.5 − 13.5 = 14 miles; Δtime = 4 − 2 = 2 hours.
Average speed = 14 / 2 = 7 miles per hour.

From hour 4 to hour 7:
Δdistance = 48.5 − 27.5 = 21 miles; Δtime = 7 − 4 = 3 hours.
Average speed = 21 / 3 = 7 miles per hour.

He neither sped up nor slowed down — his average speed stayed the same (7 mph).