A certain drug is eliminated from the bloodstream with a half-life of 34 hours. Suppose that a patient receives an initial dose of 90 mg of the drug at midnight. a. How much of the drug is in the patient's blood at noon later that day? b. When will the drug concentration reach 45% of its initial level? a. The reference point is If t is measured in hours, what is the exponential decay function? y(1) = (Type an expression. Do not round until the final answer. Then round coefficients to six decimal places as needed.) How much of the drug is in the patient's blood at noon later that day? There are approximately mg of of the drug in the patient's blood at noon later that day. (Do not round until the final answer. Then round to two decimal places as needed.) b. When will the drug concentration reach 45% of its initial level? After approximately hours, the drug concentration will reach 45% of its initial level. (Do not round until the final answer. Then round to two decimal places as needed.)