Economics – The interaction of demand and supply | e-Consult

The demand for petrol and cars exhibits a positive relationship because they are complements. This means that the consumption of one good increases the demand for the other. People who own cars require petrol to operate them. Therefore, an increase in car ownership will lead to an increase in petrol demand, and a decrease in car ownership will lead to a decrease in petrol demand.

A change in the price of cars will have an indirect effect on petrol demand. If car prices increase, fewer people will purchase cars, leading to a decrease in the overall demand for petrol. Conversely, if car prices decrease, more people will buy cars, increasing the demand for petrol. The magnitude of this effect will depend on the price elasticity of demand for both cars and petrol. If demand for petrol is relatively inelastic (meaning quantity demanded doesn't change much with price), the impact of car price changes on petrol demand will be smaller.

For a petrol retailer, understanding this relationship is crucial. A decrease in car ownership (due to higher car prices) would likely lead to a decrease in petrol sales, potentially impacting profitability. The retailer might consider strategies to mitigate this, such as offering loyalty programs or promoting other services (e.g., car washes) to maintain revenue. They might also consider targeted advertising towards existing car owners.