Question

这道题怎么做！！帮忙！！数学题！

4) Let A,B, and C be any three events defined on a sample space S. Let N(A), N(B), N(C),N(A ∩ B), N(A∩C), N(B∩C), and N(A∩B∩C) denote the numbers of outcomes in all the different intersections in which A, B, and C are involved. Use a Venn diagram to suggest a formula for N(A ∪ B ∪ C). [Hint: Start with the sum N(A) + N(B) + N(C) and use the Venn diagram to identify the “adjustments” that need to be made to that sum before it can equal N(A ∪ B ∪ C).] As a precedent, note that N(A∪B)=N(A)+N(B)−N(A∩B). There, in the case of two events, subtracting N(A ∩ B) is the “adjustment.”

Answer 1

4) Let A,B, and C be any three events defined on a sample space S. Let N(A), N(B), N(C),N(A ∩ B), N(A∩C), N(B∩C), and N(A∩B∩C) denote the numbers of outcomes in all the different intersections in which A, B, and C are involved. Use a Venn diagram to suggest a formula for N(A ∪ B ∪ C). [Hint: Start with the sum N(A) + N(B) + N(C) and use the Venn diagram to identify the “adjustments” that need to be made to that sum before it can equal N(A ∪ B ∪ C).] As a precedent, note that N(A∪B)=N(A)+N(B)−N(A∩B). There, in the case of two events, subtracting N(A ∩ B) is the “adjustment.”

Answer 2

N(AUBUC)=N(A)+N(B)+N(C)-N(A∩B)-N(B∩ C)-N(A∩C)+N(A∩B∩C).

图就不画了，大概就是画三个圆，两两各有相交，并且中间有一块三个都相交就行了，有点像红黄蓝三色图。
希望可以帮到你:)

Answer 3