
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 store sold some pens on the first day. On the second day, after reducing the price of each pen by 1 yuan, it sold 100 more pens. On the third day, after increasing the price of each pen by 3 yuans compared to the previous day, it sold 200 fewer pens than the previous day. If the revenue from selling pens was the same on all three days, what was the price per pen on the first day in yuan?

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