
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
Four years ago, there were 30 trailers in River Park with an average age of 12 years. At that time, a group of brand new trailers was added to River Park. Today, the average age of all the trailers in River Park is 10 years. How many new trailers were added four years ago?

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