
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 city, the taxi fare standard is: within 4km, the fare is 10 yuan (including 4km), for the part exceeding 4km but not exceeding 18km, the fare is 1.2 yuan/km; for the part exceeding 18km, the fare is 1.8 yuan/km.

1. Establish the functional relationship between the fare *y* and the mileage *x* without considering the waiting time fee.
2. A person paid a taxi fare of 30.4 yuan. How many kilometers did he travel?

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