Question 1157493: How many liters each of a 15% acid solution and a 65% acid solution must be used to produce 70 liters of a 30% acid solution? Answer by ikleyn(52782) (Show Source):
Let x be the volume of the 65% solution to mix.
Then the volume of the 15% solution is (70-x) liters.
The volume of the pure acid in 65% solution is 0.65x liters..
The volume of the pure acid in 15% solution is 0.15*(70-x) liters.
The volume of acid solution in the final mixture is the sum of that in ingredients.
It gives you this equation
0.65x + 0.15*(70-x) = 0.30*70.
From the equation, express x and calculate
x = = 21 liter.
ANSWER. 21 liter of the 65% solution, and the rest, 70-21 = 49 liters of the 15% solution.
CHECK. 0.65*21 + 0.15*49 = 21 liter of the pure acid = 0.30*70. ! Precisely correct !
