Question

Two solutions of salt water contain 0.03% and 0.18% salt respectively. A lab technician wants to make 1 liter of solution which contains 0.12% salt . How much of each solution should she use?

Answer 1

she should make use of 0.6L of 0.18% solution and 0.4L of 0.03% solution

Explanation:

Firstly, we assign variables.

Let the amount of solution 0.03 be x and the amount of solution 0.18 be y

Since the total amount we are trying to make is 1 little

what this means is that;

x + y = 1 ••••••••••(i)

Now, we make an equation for the percentage multiplied by the volume of each. That would be;

0.03x + 0.18y = 0.12(1)

0.03x + 0.18y = 0.12. •••••••••(ii)

Now from 1, we have x = 1 - y

We insert this into 2

0.03(1-y) + 0.18y = 0.12

0.03 -0.03y + 0.18y = 0.12

0.15y = 0.09

y = 0.09/0.15

y = 0.6L

But x = 1 - y

That would be 1 - 0.6 = 0.4L