Doreen is a chemist she needs to prepare 28 oz of a 9% hydrochloric acid solution find the amount of 14% solution in the amount of 7% solution she should mix to get the solution she needs

Answer 1

.14x + .07(28-x) = .09(28)

.14x -.07x = .09(28)-.07(28)

.07x =.02(28)

x = .02(28)/.07 = 8 = ounces of 14% mixed with 20 ounces of 7% to get 28 ounces of 9%

7 is within 2 of 9

14 is within 5 of 9

5/2 = 20/8

you need 2 1/2 times as much of 7% as 14%