A chemist wants to make 3 liters of a 7% acid solution by mixing a 9% acid solution and a 4 percent acid solution. How many liters of each solution should the chemist use?

May 30, 2017

$1.8$ liters of 9% solution and $1.2$ liters of 4% solution

Explanation:

In mixture problems combining two solutions write their strengths, draw a cross through a desired concentrate in the centre and find out the differences. In the above case it is as shown below.

The ratio of differences is $3 : 2$ and hence two concentrates should be mixed in this ratio.

Hence we should have $3 \times \frac{3}{5} = \frac{9}{5} = 1.8$ liters of 9% solution

and $2 \times \frac{3}{5} = \frac{6}{5} = 1.2$ liters of 4% solution