Question

How many ml of a 70% alcohol solution must be mixed with 2 ml of a 85% alcohol solution to make a 75% solution?

Answer 1

0.133 ml

Explanation:

The two available solutions to be used in the mixture are a 70% solution and a 85% solution .

x = volume of 70% solution

y = volume of 85% solution

y = 2 ml

Therefore;

0.7 x + 0.85(2) = 0.75(x+2)

0.7x + 1.7 = 0.75x + 1.5

multiply through by 10 to get rid of the decimals

7x + 17 = 7.5x +15

collecting and simplifying

-0.5 x = -0.2

divide both sides by -1.5

x = -0.2/-1.5

x = 2/15 ml or 0.1333 ml