What quantity of 75 per cent acid solution must be mixed with a 30 per cent solution to produce 945 mL of a 50 per cent solution?
Answer:525mL of 75% solution and 420mL of 30% solution must be mixed to produce 945mL of a 50% acid solutionLet x = 75% acid solutiony = 30% acid solution Equations:x + y = 945mL ----equation (1)0.75x + 0.3y = 0.5 * 9450.75x + 0.3y = 472.5multiplying by 10075x + 30y = 4725 ----equation (2)eliminating equations (1) and (2)-30(x + y = 945)-30-30x -30y = -2835075x +30y = 4725============45x = 23625x=525substitute x=525 to equation (1)525 + y = 945y = 945 - 525y = 420thus 525mL of 75% solution and 420mL of 30% solution must be mixed to produce 945mL of a 50% acid solution