6. solve: a chemist needs 30 ounces of 50% hydrochloric acid solution. in her lab, she has some 80% hydrochloric acid solution, some 60% hydrochloric acid solution, and some 40% hydrochloric acid solution. she must use 2 ounces of the 80% solution. how many ounces each of the 40% and 60% solutions must be mixed with the 2 ounces of 80% to obtain the 30 ounces of 50% hydrochloric acid solution she needs?