Speedy Courier Service delivers packages by car. The service uses the equation above to calculate , the total fee in dollars to deliver a package. In the equation, is the weight of the package in pounds, is the amount of driving time in minutes required to deliver the package, and is the number of miles the courier must drive to deliver the package. A customer has an 3-pound package that she needs delivered to a colleague 30 miles away. If the delivery fee is $54, what is the driver's average speed in miles per hour?