Answer:
5.7 liters of 5% solution and 4.3 liters of 40% solution is needed to be mixed to get 10 liters of a 20% acid solution
Explanation:
Let
x = Amount of 5% solution needed
(10 - x) = Amount of 40% solution needed
Equation:
5% of x + 40% of (10-x) = 20% of 10
0.05x + 0.40(10-x) = 0.20 * 10
Open parenthesis
0.05x + 4.0 - 0.40x = 0.20 * 10
Collect like terms
4.0 - 0.35x = 2.0
Add 0.35x to both sides of the equation
4.0 = 2.0 + 0.35x
Subtract 2.0 from both sides of the equation
2.0 = 0.35x
Divide both sides by 0.35
2.0 / 0.35 =x
5.7 = x
5.7 liter of the 5% solution is needed
Next is to find the amount of 40% solution needed
(10 - x) = Amount of 40% solution used
Amount of 40% solution used = 10 - 5.7
= 4.3
4.3 liters of 40% solution is needed