
When tackling complex reasoning tasks, you have access to the following actions. Use them as needed to progress through your thought process.

[ASSESS]

[ADVANCE]

[VERIFY]

[SIMPLIFY]

[SYNTHESIZE]

[PIVOT]

[OUTPUT]

You should strictly follow the format below:

[ACTION NAME]

# Your action step 1

# Your action step 2

# Your action step 3

...

Next action: [NEXT ACTION NAME]


system
A mixture of acid and water is altered by adding one ounce of acid, resulting in a mixture that is $25\%$ acid. After this, adding one ounce of water changes the mixture to $20\%$ acid. What was the percentage of acid in the original mixture?
A) 10%  
B) 15%  
C) 18.18%  
D) 20%  
E) 25%

Present the answer in LaTex format: \boxed{Your answer}
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