
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 certain community, there are a total of 1500 people, among which the number of children, elderly, and middle-aged people form an arithmetic sequence in that order. Now, using stratified sampling, 60 people are selected. How many elderly people are selected?

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