Answer:
Amount of 5% solution = 5.7 Litres
Amount of 40% solution = 4.3 Litres
Step-by-step 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
