To find the distance a car would travel using 90 liters of petrol, we need to know the fuel consumption rate of the car, i.e., how many kilometers the car can travel per liter of petrol. This can be found by using the formula:

$\text{Distance} = \text{Fuel consumption rate} \times \text{Amount of petrol}$

In this case, we know that the amount of petrol is 90 liters, but the fuel consumption rate is missing. Could you provide that information, or if not available, let me know the distance covered with a certain amount of fuel?

Let me know if you'd like more details!

Follow-up questions:

1. How many kilometers does the car travel on 1 liter of petrol?
2. What is the car's average speed?
3. Is the driving done under highway or city conditions (fuel consumption might differ)?
4. Do you have the previous distance covered with a known amount of fuel?
5. Are there any other factors, such as the car model or road conditions, to consider?

Tip: Knowing the car's fuel efficiency in terms of kilometers per liter (km/l) helps you estimate travel distances efficiently.