8 miles = 12874.8m Total distance = 16 miles = 25749.5m time = distance/velocity First instance, t =12874.8/24 = 536.45 Second instance, t = 12874.8/30 = 429.16 Total time = 536.45 + 429.16 = 965.61 Average velocity = Total distance / Total time = 25749.5/965.61 = 26.67 m/s