Maria wants to make fruit punch for a birthday party. She needs to mix three parts ginger ale, two parts cranberry juice, and one part orange juice. Ginger ale costs $2.00 per gallon, cranberry juice costs $4.00 per gallon, and orange juice costs $5.00 per gallon. Maria only has $38 dollars to spend on the ingredients for punch. How many gallons can she make? (Only an algebraic solution can receive full credit.)