Perfect Substitutes of Consumption | Consumer Behaviour

Perfect Substitutes: In some cases of consumption, a two-good (X and Y) consumer may prefer to substitute one of the goods, say, X, for the other good Y at a constant rate, to keep his level of utility constant, i.e., MRSX,Y = constant. For example, he may always want to substitute one red pencil for one blue pencil, to keep [...]