5. (5 points) The number of yeast cells in a laboratory culture increases rapidly initially, but levels off eventually. The population can be modeled by the function n = f(t) = = a 1 + be-0or : where / is measured in hours. At time / = 0 the population is 30 cells and is increasing at a rate of 15 cells/hour. Determine how fast the population of yeast cells is changing after 2 hours