Answer: 0.5 tablet per dose
Explanation: If the patient is prescribed furosemide 40 mg by mouth twice a day, they need to take a total of 40 mg + 40 mg = 80 mg per day.
Since the medication available is in 80 mg/tablet strength, the patient should receive 1 tablet per day, as one 80 mg tablet meets the total daily dosage requirement of 80 mg.