
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]


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Given that a school conducted a survey to understand the students' learning situation, they used stratified sampling to select 81 students from a population of 1000 grade 10 students, 1200 grade 11 students, and an unknown number of grade 12 students, and it is known that 30 grade 11 students were selected, determine the value of $n$.

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