Plzzz ! marie mixes 16 liters of 18% acid solution with a 27% acid solution, which results in 21% acid solution. let x represent the number of liters of 27% 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 27% acid solution in the mixture? 1. y = x + 16; 0.27y = 0.21x + 2.88 2. y = x + 16; 0.21y = 0.27x + 2.88 3.y = x + 16; 0.21y = 0.27x + 4.32 4. y = x + 16; 0.27y + 2.88x = 0.21