Problem:
Set has elements, and set has elements. What is the smallest possible number of elements in , the union of and ?
Answer Choices:
A.
B.
C.
D.
E.
Solution:
The union must contain all of the elements of , so it has at least elements. It is possible that is a subset of , in which case there are no additional elements.
The problems on this page are the property of the MAA's American Mathematics Competitions