Respuesta :
Answer:
a. 4600
b. 6200
c. 6193
Step-by-step explanation:
Let [tex]n(A)[/tex] the number of elements in A.
Remember, the number of elements in [tex]A_1 \cup A_2 \cup A_3[/tex] satisfies
[tex]n(A_1 \cup A_2 \cup A_3)=n(A_1)+n(A_2)+n(A_3)-n(A_1\cap A_2)-n(A_1\cap A_3)-n(A_2\cap A_3)-n(A_1\cap A_2 \cap A_3)[/tex]
Then,
a) If [tex]A_1\subseteq A_2, n(A_1 \cap A_2)=n(A_1)=200[/tex], and if [tex]A_2\subseteq A_3, n(A_2\cap A_3)=n(A_2)=1000[/tex]
Since [tex]A_1\subseteq A_2\; and \; A_2\subseteq A_3, \; then \; A_1\cap A_2 \cap A_3= A_1[/tex]
So
[tex]n(A_1 \cup A_2 \cup A_3)=\\=n(A_1)+n(A_2)+n(A_3)-n(A_1\cap A_2)-n(A_1\cap A_3)-n(A_2\cap A_3)-n(A_1\cap A_2 \cap A_3)=\\=200+1000+5000-200-200-1000-200=4600[/tex]
b) Since the sets are pairwise disjoint
[tex]n(A_1 \cup A_2 \cup A_3)=\\n(A_1)+n(A_2)+n(A_3)-n(A_1\cap A_2)-n(A_1\cap A_3)-n(A_2\cap A_3)-n(A_1\cap A_2 \cap A_3)=\\200+1000+5000-0-0-0-0=6200[/tex]
c) Since there are two elements in common to each pair of sets and one element in all three sets, then
[tex]n(A_1 \cup A_2 \cup A_3)=\\=n(A_1)+n(A_2)+n(A_3)-n(A_1\cap A_2)-n(A_1\cap A_3)-n(A_2\cap A_3)-n(A_1\cap A_2 \cap A_3)=\\=200+1000+5000-2-2-2-1=6193[/tex]