Automobiles have different fuel economies, and commuters drive different distances to work or school. Assume that a state section of Transportation is interested in analyzing average monthly fuel consumption of commuters in a certain city. The DOT might sample a group of commuters and collect information on the number of miles driven per day, number of driving days per month, and fuel economy of their cars. Develop a model for the amount of gasoline consumed, using the symbols for the data given below.

G = gallons of fuel consumed per month
m = miles per day driven to and from work or school
d = number of driving days per month
f = fuel economy in miles per gallon