Dear,

Great question! Allow me to provide clarification on why the proposed solution is correct. The two numbers you are comparing represent the demand and the supply.

Regarding the demand side, as per the assumptions outlined in the provided solution, on average, a vehicle consumes 9 liters of gasoline each day. This is an estimate that suggests that, if we consider the 2.5 million vehicles in Paris, each of them, on average, consumes 9 liters of gasoline daily.

On the supply side, the case aims to determine the average amount of gasoline filled into each car when visiting a gas station (assuming that if a vehicle goes to a gas station, it will fill up the tank completely). Based on the provided assumptions, this value is calculated to be 60 liters. It's important to note that this doesn't imply that every vehicle in Paris will refill with exactly 60 liters of gasoline daily. Instead, it signifies that, at full capacity, each gas station will, on average, serve 400 vehicles, and each of these vehicles will request, on average, a refill of 60 liters.

As you can see, it's unreasonable to assume that all cars will refill their tanks every day. In fact, if you multiply the average number of cars served by each gas station by the estimated number of gas stations in Paris, you'll arrive at a smaller number, which corresponds to the number of cars visiting the gas stations in Paris (approximately 375,000).

An important assumption to consider here is that gas stations are sized to operate at full capacity, meeting all the demand (i.e., no market gap). Additionally, this analysis does not take into account other vehicles that require gasoline, such as motorcycles.

I hope this clarifies the situation for you. Please don't hesitate to reach out if you have any further questions.

Best regards,
Antonio