
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
Given two tourist attractions, A and B, connected by a 5km straight waterway, a cruise ship travels at a speed of x km/h (considering safety regulations, 20 ≤ x ≤ 50). The fuel cost per hour is $(\frac{x}{40} - k)$ ten thousand yuan (k is a constant, and $\frac{1}{15} ≤ k ≤ \frac{1}{5}$), and other costs are $\frac{1}{x}$ ten thousand yuan per hour.
1. If the cruise ship travels at a speed of 30 km/h, the fuel cost per hour is $\frac{5}{8}$ ten thousand yuan. To ensure that the total cost per hour does not exceed $\frac{9}{10}$ ten thousand yuan, find the range of x.
2. Find the minimum total cost for a one-way trip.

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