
Answer:
  v = 72 km / h
Explanation:
The definition of average speed is the distance traveled between the time interval
     v = Δx / Δt
let's find the distance traveled
    x = 60 + 30
    x = 90 km
time spent, all time must be included, travel time and when stopped
    t = 0.45 + 0.15 + 0.5+ 0.15
    t = 1.25 h
we substitute in the initial equation
   v = 90 / 1.25
    v = 72 km / h
in going from one city to the other