Suppose Set B contains 69 elements and the total number elements in either Set A or Set B is 107. If the Sets A and B have 13 elements in common, how many elements are contained in set A?

1 answer

Union is 107
Intersection is 13

draw Venn diagram

69 + A alone = 107
so
A alone = 38
plus A and B = 38+13 = 51