Question - Calculate Rate of Change in Distance with Respect to Time

Let s(t) be the distance travelled as a function of time t.

The rate of change of distance with respect to time is the derivative of s with respect to t, which is the velocity v(t) = \frac{ds}{dt}.

For constant velocity, the rate of change of distance with respect to time is constant.

The rate of change over the 80 km travelled is simply the constant velocity, which can be calculated as v = \frac{\Delta s}{\Delta t} where \Delta s = 80 \text{ km} and \Delta t = t_f - t_i, the time taken to travel the last 80 km.

Without additional specific information about the time interval \Delta t or the actual function s(t) for the motion, we cannot compute a numerical value for the rate of change.