To 3 kg of water was added 9 kg of a 70% sulfuric acid solution. Determine the concentration of the resulting solution.

According to the condition, a 70% solution of sulfuric acid is given, the total mass of which is 9 kilograms.

We calculate the mass of acid in this solution:

9 * 70% = (9/100) * 70 = 0.09 * 70 = 6.3 kg.

Let’s calculate what the mass of water in solution is equal to:

9 – 6.3 = 2.7 kg.

After 3 kilograms of water was added to the solution, the mass of water in it became equal to 5.7 kilograms:

2.7 + 3 = 5.7 kg.

Let’s calculate the total mass of the new solution:

5.7 + 6.3 = 12 kg.

Let’s calculate the percentage of acid in the new solution:

6.3 / 12 = 0.525 = 52.5%.