Joint Demand:
1. When two or more goods are demanded jointly to satisfy a single want, it is called joint or complementary demand.
2. E.g. of joint demand are car and petrol, ink cartridge and printers, mobile and sim card.
3. A rise in demand for one product will lead to a rise in the demand for other and vice versa.
4. In case of joint demand an increase in price of one good will reduce the demand for its joint product i.e. a rise in price of petrol will reduce the demand for car.
5. The demand for joint products is inelastic.
Composite Demand:
1. When goods are demanded for several uses, it is the case of composite demand.
2. E.g. of composite demand are for electricity, coal, steel, sugar, etc.
3. A change in demand for one use will affect the supply in other use.
4. In case of composite demand, an increase in the price of product will reduce its demand for different uses. Electricity / coal will be put to only important uses when its price rises.
5. The demand for composite commodities is elastic.
