
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 school currently has 210 freshmen, 270 sophomores, and 300 seniors. A stratified sampling method is used to randomly select $n$ students from these three grades for a questionnaire survey. If it is known that 7 freshmen were selected, then the number of sophomores selected is __________.

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