
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
Through investigation and statistics, for a certain model of car driving at a constant speed, the fuel consumption per hour $y$ (liters) as a function of the driving speed $x$ (km/h) can be represented as $y= \frac {1}{120000}x^{3}- \frac {1}{50}x+ \frac {18}{5}$ $(0 < x\leqslant 100)$. Given that the distance between two places A and B is $100$ kilometers, under the condition that the constant driving speed does not exceed $100$ km/h, the fuel consumption of this model of car from A to B is denoted as $f(x)$ (liters).  
(Ⅰ) Find the analytical expression of the function $f(x)$;  
(Ⅱ) Discuss the monotonicity of the function $f(x)$, at what value of $x$ is the fuel consumption $f(x)$ the least? What is the minimum consumption in liters?

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