Problema Solution
Doreen is a chemist with Gemco Pharmaceutical. She needs to prepare 12 ounces of a 9% hydrochloric acid solution. Find the amount of a 4% solution and the amount of a 12% solution she should mix to get this solution.
Answer provided by our tutors
if you mixed equal amounts of the two solutions; the strength of the resulting mixture would be the average
___ in this case, 12 ounces of 8%
___ so the stronger solution must be more than half of the mixture
(4%)(x) + (12%)(12 - x) = (9%)(12)
4x + 144 - 12x = 108 ----->36 = 8x
4.5 = x
4.5 oz of 4% and 7.5 oz of 12%