5.a) since the distance is 140km, and the time is 2hours, and we need the speed in km/h, we have to divide the distance by time, and we will get the speed: s=d/t = 140km/2h = 70km/h
b) the distance is 43km, and the time is 30 minutes, which is 0,5hours, we do the same thing here, with given formula : s=d/t = 43km/0,5h = 86km/h