What is joint demand

Answer :

It refers to the demand for two or more goods which are used jointly or demanded together for example car and petrol, bread and butter, pen and refill, milk and sugar etc.change in any one commodity affects the other like increase in demand for cars leads to increase in demand for petrol, since both are used together, a car without petrol is of no use.Also a rise in the price of cars will lead to not only a fall in the demand for cars, but also a fall in the demand of petrol and vice versa.When the price of car rises it become more costly so people will demand less cars and thereby leading to fall in the demand of petrol.When the price of car falls it become relatively cheaper so people will demand more cars and thereby leading to increase in the demand of petrol.