Faith mixes 14 liters of 12% acid solution with a 30% acid solution, which results in an 18% acid solution. let x represent the number of liters of 30% acid solution used, and let y represent the number of liters of mixture. which system of equations can be used to find the number of liters of 30% acid solution in the mixture? a. y=x + 14; 0.18y = 0.3x + 1.68 b. y=x + 14; 0.12y = 0.3x + 1.68 c. y=x + 14; 0.12y = 0.3x + 4.2 d. y=x + 14; 0.18y = 0.3x + 4.2