Suppose that A is the set of sophomores at your school and B is the set of students in discrete structures...?

Please help with my homework. I'm confused.





Suppose that A is the set of sophomores at your school and B is the set of students in discrete structures at your school. Express each of these sets in terms of A and B.





a) The set of sophomores taking discrete structures.__________________





b) The set of sophomores at your school who are not taking discrete math._________________





c) The set of students at your school who are either sophomores or are taking discrete math._____________________





d) The set of students at your school who either are not sophomores or are not taking discrete math___________________

Suppose that A is the set of sophomores at your school and B is the set of students in discrete structures...?
a) A intersect B (A and B)





b) A intersect Bnot (A and B' )





c) A union B (A or B)





d) Anot union Bnot (A' or B' )








Hope this helps!
Reply:a) This would be the students who are both sophomores and taking the class, so they're in both sets A and B. So the answer is


A∩B





b) If B is the set of students taking the class, then ~B (the complement of B) are the students not taking it. So the sophmores not taking it is represented by the set


A∩(~B)





c) This is everybody in both sets, so take the union: A U B.





d) The set of students who aren't sophomores is ~A, so the answer is


~A U (~B).
Reply:sure. A is the total # of sophomores, and B is the total students (of all grades) taking discrete structures,


so


a) the set that includes set A and set B (intersection)


which is the absolute value of #of Set B - Set A


b) the number who are not taking it is Set A - the answer to the question before this


c) that's the union of set A and set B, - number in both. So, in this case it's set A + set B - the answer to a)


d) impossible with the given information right now, since you don't know how many kids are in the other grades