Question 29329
The total time taken for the trip is 3 hr and the total average speed is 75 km/h.


For this problem, average speed = average velocity = Δx/Δt


Therefore, Δx=(75 km/h)(3 hr) = 225 km


So the displacement for the remaining 1 hr is 225-(2)(80)= 65 km


Thus, you must drive 65 km/hr (Answer)