A restaurant sells ice cream and frozen yogurt. The restaurant makes one order for ice cream and frozen yogurt per week, and the store has enough freezer space for 110 gallons of both products. A gallon of frozen yogurt costs $ 0.85 and a gallon of ice cream costs $0.95, and the restaurant budgets $90 each week for these products. The manager estimates that each week the restaurant sells at least twice as much ice cream as frozen yogurt. Profit per gallon of ice cream is $4.30 and profit per gallon of frozen yogurt is $3.90.
a. Formulate a linear programming model for this problem.
b. Solve this model using graphical analysis.