6. A cup of coffee contains approximately 100 mg of caffeine. After you drink a cup of coffee, the amount of caffeine in your bloodstream is reduced by about 13% per hour. (7 Marks) a) Write an equation to represent the mass of caffeine, y milligrams, in your bloodstream x hours after you drink a cup of coffee. b) Estimate how many milligrams of caffeine is in your bloodstream after: iii) 8 hrs i) 2 hrs ii) 4.5 hrs