Hi 60 liters 45% acid, using 2 times as much of the 70% solution as the 25% solution. .15(60L - 3x)) + .25(x) + .70(2x) = .45(60L) .15(60L) - .45x + .25(x) + 1.4x = .45(60L) x = .30(60L)/1.2 = 15L of the 25% solution 15L of the 25% solution, 30L of the 70% solution & 15L of 15% solution 27=27 checks Wish You the Best in your Studies.