Final answer:
The questions relate to statistical and financial mathematics, such as calculating commissions, conducting surveys, and estimating sales, which are suitable for high school students.
Step-by-step explanation:
The context provided mentions various scenarios involving calculations and statistical analysis of different situations such as sales commissions, shopping preferences, store visits, car sales, salary comparisons, and DVD rental estimates. This indicates that the subject of the questions is Mathematics, specifically in areas related to statistics, percentages, and financial mathematics. The level of mathematical knowledge required for solving these problems suggests that the questions are appropriate for a High School grade level.