Consider the following problem that you intend to set up as a linear programming problem. Gillians restaurant has an ice cream shop where it sells two main products: ice cream and frozen yogurts. The restaurant makes one order for ice cream and yogurt each week, and the store has enough freezer space for 115 gallons total for both products. A gallon of frozen yogurt costs the restaurant $0.75 per gallon and a gallon of ice cream costs $0.93, and the restaurant budgets $90.00 each week for both products. The manager, based on historical demand, would like to sell more ice cream than frozen yogurt. Profit per gallon of ice cream is $4.00 and profit per gallon of frozen yogurt is $3.00. The restaurant would like to optimize its weekly order to maximize its weekly profitability.

How many decision variables are there?