Answer:
10 ml
Explanation:
The concentration of the acid solution Chelsea adds to the 25 milliliters of 30% acid solution = 65%
The concentration of the acid solution Chelsea requires = 40%
The volume, X, of the 65% acid solution required is given as follows;
65% × X + 30% × 25 = 40% × (25 + X)
As fractions, we have;
0.65 × X + 0.3 × 25 = 0.4 × (25 + X)
0.65·X + 7.5 = 10 + 0.4·X
0.65·X - 0.4·X = 10 - 7.5
0.25·X = 2.5
X = 2.5/0.25 = 10
X = 10 ml
The volume of the 65% acid that should be added to create a solution that is 40% acid = 10 ml.
