JAMB - Economics (2011 - No. 6)
If the demand for one commodity excludes another, it is said to be
complementary demand
competitive demand
composite demand
derived demand
Maelezo
competitive demand is a market situation where a prospective buyer could choose between two competing products and still receive roughly the same level of satisfaction. The selection of one product which are normally substitutes would lead to the exclusion of the other product. Example if mr X intends to buy detergent, he can either choose to buy omo or sunlight detergent but not the two. Choosing between these two alternatives is what is referred to as competitive demand.