Final answer:
The average flow rate of oil into the truck is calculated by converting the amount filled in 40 minutes to an hourly rate, yielding an average flow rate of 750 gallons per hour.
Step-by-step explanation:
To find the average flow rate of oil into the truck in gallons per hour, we use the information given: 500 gallons are filled in 40 minutes. To convert the flow rate from gallons per 40 minutes to gallons per hour, you need to set up a proportion or use a direct multiplication conversion factor. Since there are 60 minutes in an hour, you would calculate the flow rate as follows:
Flow rate = (500 gallons / 40 minutes) × (60 minutes / 1 hour) = 750 gallons/hour.
Therefore, the average flow rate is 750 gallons per hour.