
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
Xiao Zhang drives a car from the foot of the mountain at point $A$, reaches the top of the mountain, then descends to the foot of the mountain at point $B$, and finally returns to point $A$ along the same route. The car's speed uphill is 30 kilometers per hour, and its speed downhill is 40 kilometers per hour. When Xiao Zhang returns to point $A$, he finds that the return trip took 10 minutes less than the outbound trip, and the car's odometer increased by 240 kilometers. How many hours did Xiao Zhang spend on this round trip?

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