Answer
See the solution.
Work Step by Step
a) $A \cap B$ is the set of elements that are in both $A$ and $B$. So $A \cap B$ is the set of students living one mile within a school and walking to classes.
b) $A \cup B$ is the set of all elements that are in $A$, or in $B$, or in both $A$ and $B$. So $A\cup B$ is the set of students living one mile within a school and/or walking to their classes.
c) $A-B$ is the set of elements that are in $A$ but not in $B$. So $A-B$ is the set of students who live one mile within a school but do not walk to classes.
d)$B-A$ is the set of all elements that are in $B$ but not in $A$. So $B-A$ is the set of students who walk to classes but do not live within one mile of a school.