Question 631589
In order to get the UNION of two sets, you can ADD the number of members of the two sets together, and SUBTRACT the OVERLAP.  The OVERLAP is actually the INTERSECTION.  This gives the following formula:


n(A) + n(B)-n(A intersection B)=n(AUB)
20 + n(B) -16 = 58
4 + n(B) = 58
n(B) = 58-4 = 54


Dr. Robert J. Rapalje, Retired
Seminole State College of Florida