
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 certain civil aviation regulation allows passengers to carry a kilograms of goods for free. However, for goods exceeding a kilograms, a certain fee is charged. The fee is calculated as follows: the weight of the goods carried by the passenger, b kilograms (b > a), multiplied by 20, minus 300, gives the fee that should be paid.
1. Shen Tao carried 50 kilograms of goods. How much fee should he pay?
2. Xu Min paid a fee of 100 yuan. How many kilograms of goods did he carry?
3. What is the value of a in this context?

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