There are always two types of relationships between two quantities. Either the relationship is Directly proportional or it would be Indirectly proportional. Directly proportional is a relation in which one quantity increases with the increase of the other quantity and vice versa. Whereas in indirectly proportional relationship, one quantity decreases with the increase of the other quantity and vice versa.
Now in this question, the given quantities are Distance traveled by a car and the amount of gas in the car. These two quantities have indirect proportional relationship. When the Distance traveled by the car increases, the amount of gas in the car decreases and vice versa.
