
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
Xiaoming has to pass through a crossroad with traffic lights on his way to school every day. It is known that the green light at the crossroad lasts for $40$ seconds, and the red light lasts for $50$ seconds. Given that Xiaoming arrives at the crossroad at a random time every day, calculate the probability that Xiaoming has to wait for at least $20$ seconds at the crossroad when going to school.

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