Gabe Amodeo, a nuclear physicist, needs 60 liters of a 40% acid solution. He currently has a 30% solution and a 60% solution. How many liters of each does he need to make the needed 60 liters of 40% acid solution?
.30 x + .60 ( 60-x) = .40 (60) solve for x = 30 % amount then 60% amount = 60 - x