Java Inheritance example

Question

Can somebody give me a hand with this task? What is the approach I should take to solve the following problem?
  TASK

Given the 'Vehicle' class briefly described with the average consumption (liters per 100 km), extend it
with the Auto class.

  The Auto class manages the fuel tank
  whose maximum capacity is 120 liters per car.

  The Auto class must offer, in addition to the manufacturer,
  the following methods:

  1) The 'travel' method allows you to make a trip with
  the kilometers provided as a parameter, provided that the
  petrol from the tank and vehicle consumption allow it.
  The kilometers traveled by each trip are stored for
  support the calculation of information on the use of the car.
  For simplicity, we assume a maximum of 100 trips.

  2) The 'refueling' s method allows refueling
  if the maximum tank capacity is not exceeded. The method
  returns the number of kilometers traveled since the last
  refueling done.

3) Finally, the 'average' method returns the kilometers that are averaged
are covered in one journey.

Answer 1

Hello Albin Sopaj

You need to write an abstract class Vehicle. This is the super class.
Here you need only to add the methods without body.

For example:

public void travel(double kilometer);

Then write the class Auto which extends Vehicle class.
Here you override each method of Vehicle and fill them with functionality.

about abstract class:
https://www.sololearn.com/learn/Java/2166/

Answer 2

public abstract class Vehicle{

}

I don't think that travel() need to return a value.

Answer 3

Should I write an abstract or public class?
And I'm not sure if the travel method should or should not return a value (this is to say shall we use a void type) ?