Help please with these

6. The velocity of a runner lost in the woods is 7. The table below shows a car's instantaneous shown below. velocity at certain points as it moves along a straight road. t (sec) 0 7 15 20 v(t) (fu/sec) 32 28 20 30 a) Find the average acceleration from t = 7 seconds sec to t = 15 seconds. Please indicate units of measure. b) Explain why there must be a time c on the a) Find the velocity of the runner at t = 3 . interval 15