Final answer:
Approximately 33.1 milligrams of the drug remain in the patient's bloodstream after 5 hours.
Step-by-step explanation:
To find the amount of milligrams of the drug remaining in the patient's bloodstream after 5 hours, we can substitute t=5 into the given equation.
D(t) = 90e⁻⁰.²ᵗ
D(5) = 90e⁻⁰.²(5)
D(5) = 90e⁻¹
Using a calculator, we can evaluate e⁻¹ which is approximately 0.368.
D(5) = 90 * 0.368
D(5) = 33.12
Therefore, approximately 33.1 milligrams of the drug remain in the patient's bloodstream after 5 hours.