Question

A scientist need 10 L of a 20% acid solution for an experiment where she had only a 5% solution and a 40% solution to the nearest 10th of a liter about how many liters of the 5% in the 40% solution should she miss to get the solution she needs

Answer 1

Amount of 5% solution = 5.7 Litres

Amount of 40% solution = 4.3 Litres

Explanation:

First, of all, let x be the amount of 5% solution used

Since, the scientist needs 10 L of solution, then;

Let 10 - x be the amount of 40% solution used

Now, we are told that she needs 10 L of a 20% acid solution.

This means that;

5%x + 40%(10 - x) = 20%(10).

Simplifying this gives;

0.05x + 0.40(10 - x) = 0.20 × 10

Expanding the bracket gives;

0.05x + 4 - 0.4x = 2

0.4x - 0.05x = 4 - 2

0.35x = 2

x = 2/0.35

x ≈ 5.7 litres

Thus, she will need to mix 5.7 liters of the 5% solution.

Since 10 - x be the amount of 40% solution used , then;

the amount of 40% solution = 10 - 5.7 = 4.3 litres