You have 100 ml each of 400 mg/ml sodium phosphate, 250 mg/ml sodium chloride, and 100 mg/ml potassium nitrate. You want to make one liter of a solution containing 10 mg/ml sodium phosphate, 10 mg/ml sodium chloride, and 10 mg/ml potassium nitrate. How much of each starting solution do you need to use, and how much water do you need to add?