Complementary Demand or Joint Demand:
1. When two or more goods are demanded jointly to satisfy one want, it is called complementary or joint demand.
2. E.g. bread and butter, car and petrol, mobile and sim card.
3. A rise in demand for one product will lead to a rise in the demand for the other and vice versa.
4. The cross elasticity of demand is negative.
5. When price of one commodity rises the demand for the other commodity i.e. its joint product falls. When price of car falls the demand for petrol rises.
6. The demand curve has a negative slope.
Competitive Demand Demand:
1. When two goods are close substitutes i.e. the demand for one competes with that of the other it is a case of competitive demand.
2. E.g. tea or coffee, pepsi or coke, petrol or diesel, Lux or Dove.
3. Rise in demand for one product will lead to a fall in the demand for other and vice versa.
4. The cross elasticity of demand is positive.
5. When the price of one commodity rises, the demand for the substitute commodity rises. When price of tea rise, the demand for coffee increases.
6. The demand curve has a positive slope.
