4) (16 pts) A dose of a drug is injected into the body of a patient. The drug amount in the body decreases at the rate of 10% per hour. This follows the differential equation of = -0.1A, where A is the amount of drug in the body and t is time in hours. a. If a dose of 10 cc (cubic centimeters) is given to the patient initially, how long does it take for half of the drug to remain in the body? Give the exact answer. b. At what rate is the amount of drug in the body changing after 5 hours? (Assume same initial dose of 10cc.) Round to 2 decimal places