Pure acid is to be added to a 10% acid solution to obtain 90L of 58% solution. What amounts of each should be used? How many of 100% pure acid should be used to make the solution?
x = 10% amount 90-x = 100% (pure) amount
acid in ingredients = acid in final product
.10x + 1.0(90-x) = .58(90) solve for 'x' the 10% amount
then pure amount to use = 90-x