The drug Valium is eliminated from the bloodstream exponentially with a half-life of 36 hours. Suppose that a patient receives an initial dose of 80 milligrams of Valium at midnight.

a. How much Valium is in the patient's blood at noon on the first day?

b. Estimate when the Valium concentration will reach 45% of its initial level.

a. How much Valium is in the patient's blood at noon on the first day?

There is approximately____ mg of Valium in the patient's blood at noon on the first day.

(Round to the nearest tenth as needed.)