Mixed 16 g of a 9% solution and 10 g of a 2% solution of the same substance.

Mixed 16 g of a 9% solution and 10 g of a 2% solution of the same substance. Find the concentration of the substance in the resulting solution.

We find the amount of substance in the first solution:
16 * 9% = 16/100 * 9 = 1.44 (g).
We do the same with the second solution:
10 * 2% = 10/100 * 2 = 0.2 (g).
We find the amount of the resulting solution:
16 + 10 = 26 (g).
The amount of substance in the new solution is:
1.44 + 0.2 = 1.64 (d).
We find the percentage of the substance or its concentration in the new solution:
1.64 * 26 * 100 = 6.30769 ≈ 6.31%.
Answer: the concentration of the substance in the new solution is 6.31%.