5. {A - 4} The distance, d, in metres travelled by a boat from the moment it leaves shore can be modelled by the function: d(t) = 0.00213 + 0.0512 + 0.3t, where t is the time, in seconds. a) Determine the average rate of change of the distance travelled during the first 20 seconds after leaving the shore. b) Estimate the instantaneous rate of change 20 seconds after leaving the shore