
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
In a city, a newspaper stand buys the "Evening News" from the publisher at a price of $0.20 per copy and sells it at $0.30 per copy. Unsold newspapers can be returned to the publisher at $0.05 per copy. In a month (considered as 30 days), there are 20 days when 400 copies can be sold each day, and for the remaining 10 days, only 250 copies can be sold each day. However, the number of copies bought from the publisher must be the same every day. How many copies should the stand owner buy from the publisher each day to maximize the monthly profit? And calculate the maximum profit he can earn in a month?

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