Algebra
posted by Amber .
A chemist needs to mix a solution containing 30% insecticide with a solution containg 50% insecticide to make 200L of a solution that 42% insecticide. How much of each solution should she use?
dealing with graphing, subst., and elimin.

let x L represent the volume of the 30% solution, then 200  x L would be the 50% solution
then...
.3x + .5(200x) = .42(200)
solve....