Answer:
46.91%
Explanation:
The first solution contains 11 * 0.25 = 2.75 L of vinegar
The second solution contains 12 * 0.67 = 8.04 L of vinegar
When mixed together, that adds up to 8.04 + 2.75 = 10.79 L of vinegar
The total volume of the combined solutions is 11 + 12 = 23 L of solution
So the new concentration is 10.79/23 ≈ 0.4691 ≈ 46.91%