The body mass of a certain type of sheep can be estimated by M(t) = 27.1 + 0.3t-0.001t where M(t) is measured in kilograms and t is days since May 25 a. Find the average rate of change of the mass of a sheep between 101 and 111 days past May 25. b. Find the instantaneous rate of change of the mass of a sheep whose age is 101 days past May 25