Answer:
b) 24
Step-by-step explanation:
We solve building the Venn's diagram of these sets.
We have that n(S) is the number of succesful students in a classroom.
n(F) is the number of freshmen student in that classroom.
We have that:
In which n(s) are those who are succeful but not freshmen and are those who are succesful and freshmen.
By the same logic, we also have that:
The union is:
In which
So
So the correct answer is:
b) 24