Bunuel wrote:

A solution that is 40% acid must be strengthened to become a solution that is 88% acid. If there are 10 ounces of the 40% solution, how much pure acid must be added?

A. 2.5 ounces

B. 18 ounces

C. 28 ounces

D. 40 ounces

E. 48 ounces

We need to make 40% acid solution into a 88% acid solution.

A1 = 40% Acid Solution

A2 = 100% Acid Solution (Pure Acid)

Final = 88% Acid Solution

A1:A2 = 1:4

If we have 10 ounces of A1, we need to have 40 ounces of A2.

Hence D

Thank you Karishma for the weighted average method.

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