Question

A chemist has 10% and 40% solutions of acid available. How many liters of each solution should be mixed to obtain 120 liters of 15% acid solution?

Answer 1

100 liters of 10% solution is used and 20 liters of 40% solution is used

Explanation:

Let "X" amount of 10% solution is used. Then the amount of 40% solution used is equal to 120-X

Now

10% of X + 40% of (120-X) = 15% of 120

On solving the above equation, we get

`0.1 X + 0.4 (120-X) = 0.15 *120\\0.1 X + 48 -0.4X = 18\\0.3 X = 30\\X = 100`liters

Amount of 40% solution used = 120 -X = 120-100 = 20 liters

100 liters of 10% solution is used and 20 liters of 40% solution is used