A nontoxic floor wax can be made from lemon juice and food-grade linseed oil. The amount of oil should be twice the amount of lemon juice. How many of each ingredient is needed to make 27 ounces of floor wax? Let x represent the number of ounces of lemon juice and y the number of ounces of linseed oil.

Complete the system of equations.

y = __

x + y = __