Answer:
a. Assuming gallons of unleaded regular is denoted by r; and unleaded premium by p.
Revenue from one gallon of unleaded regular is $1.299 and from unleaded premium is $1.379.
Revenue function = 1.299r + 1.379p
b. Cost of one gallon of unleaded regular is $1.219 and for unleaded premium is $1.289.
Cost function = 1.219r + 1.289p
c. Total profit = Revenue - Cost
= 1.299r + 1.379p - 1.219r - 1.289p
= 1.299r - 1.219r + 1.379p - 1.289p
= 0.08p + 0.09p
d. If station sells 100,000 gallons of unleaded regular and 40,000 of unleaded premium;
= (0.08 * 100,000) + (0.09 * 40,000)
= 8,000 + 3,600
= $11,600