
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
Andrey and Seva are planning to visit Borya. Andrey is at point $A$, while Borya is at point $B$, located 30 km from point $A$ along a straight highway. Seva is at point $C$, exactly midway between $A$ and $B$. They decide to leave at the same time: Andrey on a bicycle and Seva on foot, but Andrey will leave the bicycle at a predetermined place for Seva to use (Andrey will walk the remainder of the way). On bicycles, they both travel at a speed of 20 km/h, and on foot at a speed of 5 km/h. Where should the bicycle be left so that the friends can reach Borya together as quickly as possible?

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