Final answer:
The student's question pertains to Economics, focusing on how Keratiloe and Cath can improve their grades by studying areas weighted differently in their grading formulas, and general consumer responses to income changes. It also touches on factors influencing demand and supply, such as technological advances and natural disasters.
Step-by-step explanation:
The question concerns Economics, specifically regarding consumer behavior in response to income changes and factors affecting market demand and supply. Keratiloe and Cath's grades are affected by their abilities to answer marginal analysis questions and demand and supply questions, as represented by their respective grade formulae. It is not possible to determine who the 'smarter' student is based solely on these formulae, as they only reflect emphasis on different areas and not overall intelligence or understanding. When it comes to studying, Cath can realize marginal improvements by analyzing where she could maximize her scores based on the weight each type of question holds in the grading formula.
When incomes rise, consumers typically purchase more normal goods, which is evident in consumer behavior reflecting a reaction to income changes. Various factors play into this decision, like personal preferences, the marginal utility received from goods, and overall market dynamics, including supply shifts due to input costs like wages for teachers or costs for textbooks in the case of educational services. In the case of a market for goods, such as paint, changes in technology, longevity of the product, natural disasters, and production disruptions will all affect either supply or demand, depending on the nature and direction of the change.