Question

A chemist has two solutions, A and B. Solution A is 30% acid and the rest water, while solution B is 60% acid and the rest water. If equal amounts of solutions A and B are mixed to form a new solution C, what is the percentage of acid in solution C?

• A. 35%
• B. 40%
• C. 50%
• D. 45%

Answer 1

Answer: (D)

45%

Answer 2

Let's assume we have 100 ml of each solution A and B.

In solution A, there are 30 ml of acid and 70 ml of water.

In solution B, there are 60 ml of acid and 40 ml of water.

When mixed, we have a total of 200 ml of solution.

Total acid in the mixture = 30 ml + 60 ml = 90 ml.

Percentage of acid in solution $C = \left( \frac{\text{Total acid}}{\text{Total volume}} \right) \times 100$

= $\left( \frac{90 \text{ ml}}{200 \text{ ml}} \right) \times 100$

= 45%