Answer:
First, you would have to convert fl oz to gallons: 1 fl oz = 0.0078125 gal. Therefore, 4 fl oz = 0.03125 gal.
Then, you would have to convert minutes to hours: 1 minute = 0.01666 hours, or 60 minutes = 1 hour.
From here, you can divide 0.03125 gal by 0.01666 hours OR multiply 0.03125 gal by 60 minutes, giving a rate of 1.87 gallons per hour.
