Answer:
Marginal rate of substitution
Indifference curve
Step-by-step explanation:
Marginal rate of substitution is the act in which a customer substitutes some quantities of good for another and is still able to derive the same level of satisfaction . The substitution has to be marginal for the derived satisfaction to be maintained.
Indifference curve is a graphical representation of the combination of the quantities of goods that a customer perceives to be of the same value to him.
While the quantity of a good increases , the quantity of the other good decreases .
The two definitions above best describe the situation in the scenario.