A pharmacist has 18% bleach solution. How much of this solution and how much water must be mixed together to make 10 liters of a 12% solution?

x = the amount of water to add 10 - x = amount of 18% bleach to add .18(10-x)= .12 x 10 1.8 -.18x =1.2 -.18x = -.6 x = 3 1/3 liters water therefore 6 2/3 liters bleach