Linear Modeling Word Problem

Question

You are a chemist and you have a supply of a brine solution that is 40% salt and a brine that is 20% salt. You are performing a experiment that requires you to have 12 liters of a 25% brine solution. How much of the 40% solution and 20% solution do you need to add together to get the required solution? Label your answer as ___L of 40% and ___L of 20%.

Answer 1

x*.4+ (12-x)*.2 = 12*.25

solve for x

what is 12-x

answers  3 & 9