How many milliliters of a 25 solution of potassium chloride

How many milliliters of a 25% solution of potassium chloride must be added to 8 ml of pure potassium chloride to obtain a 35% solution?

Solution

Let \"x\" ml be the volume of 25 % potasium chloride solution to be added.

8 ml is the volume of pure potasium chloride solution.

percentage of potasium chloride in 25% solution = x * 25/100 = x/4 ml.

Total volume of the mixture = (x + 8) ml

(x/4 + 8) ml is the total volume of potasium chloride and is 35 % of the final mixture.

x/4 + 8 = 35 % of total solution

x/4 + 8 = (35/100) * (x + 8)

x/4 + 32/4 = 0.35 x + 0.35 * 8

(32+x) / 4 = 0.35x + 2.8

32 + x = 1.4x + 11.2

32 - 11.2 = 1.4x - x

20.8 = 0.4x

x = 52 ml