Each of 3 charities in Ginglo Kiru has 8 persons serving on its board of directors. if exactly 4 persons serve on 3 board each and each pair of charities has 5 persons in common on their boards of directors, then how many distinct persons serve on one or more boards of directors?
A. 8
B. 13
C. 16
D. 24
E. 27
How can we do this with Venn diagram
Answer is B
But can't trust this completely.
A. 8
B. 13
C. 16
D. 24
E. 27
How can we do this with Venn diagram
Answer is B
But can't trust this completely.
