When one ounce of water is added to a mixture of acid and water, the new mixture is $$20\textbackslash\%$$ acid. When one ounce of acid is added to the new mixture, the result is $$33\frac{1}{3}\textbackslash\%$$ acid. The percentage of acid in the original mixture is ($$1973$$ AHSME Problem, Question \#$$33$$) 
选项为:A:$$22\textbackslash\%$$  B:$$24\textbackslash\%$$  C:$$25\textbackslash\%$$  D:$$30\textbackslash\%$$  E:$$33\frac{1}{3}\textbackslash\%$$  请回答其中一个选项.