22. [a] [b] The population of bacteria in a laboratory experiment is given by the function: It f (x) = 30 - (e)? , where t is the time in hours simthe start of the experiment How fast is the population increasing after 2.5 hours? [A o to Determine the time, to the nearest minute after the start of the experiment [A when the population is increasing by 70 bacteria per hour. to At what rate is the population changing when the number [A of bacteria has doubled