
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 fast train and a slow train start simultaneously from two stations, one in the east and the other in the west, and meet for the first time 10 kilometers west of the midpoint. After meeting, both trains continue at their original speeds, reach the other's starting point, and then immediately return. They meet for the second time on the way back, at a point 40 kilometers away from the eastern station. What is the distance between the two stations?

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