Question

A solution of 8% boric acid is to be diluted by adding a 2% boric acid solution to it. The resulting mixture is to be more than 4% but less than 6% boric acid. If we have 640 liters of the 8% solution, how many liters of the 2% solution will have to be added?

(a) 320 liters
(b) 400 liters
(c) 480 liters
(d) 560 liters

Answer 1

To find out how many liters of the 2% boric acid solution need to be added to the 8% boric acid solution, we can set up an equation based on the principles of mixtures. The solution involves solving this equation to find the value of x.

Step-by-step explanation:

To solve this problem, we can set up an equation based on the principles of mixtures. Let's say we add x liters of the 2% boric acid solution to the 640 liters of the 8% boric acid solution. The total volume of the resulting mixture will be 640 + x liters. The equation for the concentration of boric acid in the final mixture can be written as:

Simplifying and solving this equation, we find:

x = 400 liters

So, 400 liters of the 2% boric acid solution will need to be added to the 640 liters of the 8% boric acid solution.