## Elementary Algebra

The solution is 300 ml, and the amount of acid is 30% of 300, so we obtain: The amount of acid = 30% of 300. The amount of acid = 30% $\times$ 300. The amount of acid = $\frac{30}{100}$ $\times$ 300. The amount of acid = 30 $\times$ 3. The amount of acid = 90 ml.