Question

How many ounces of 20%

hydrochloric acid solution and
70% hydrochloric acid solution
must be mixed to obtain 20
ounces of 50% hydrochloric acid
solution?

Answer 1

8 ounces of 20%, 12 ounces of 70%

Explanation:

8 ounces of 20%, 12 ounces of 70%

Explanation:

Let 'x' be the number of ounces of 20% solution and 'y' be for the 70% solution. Since the the mix is 50% of 20 ounces then: x + y = 20

0.20x + 0.70y = 0.50(20)

From the 1st equation solve for x

x = 20 - y

Substitute it to the 2nd equation: 0.2(20-y) + 0.7y = 10, 4 - 0.2y + 0.7y = 10, 0.5y = 10-4, 0.5y = 6, y = 12

Substitute to x = 20 - y

x = 20 - 12

x = 8