Question:
If A = {3, 5, 7, 9, 11}, B = {7, 9, 11, 13} and C = {11, 13, 15}, and D = {15, 17}, find:
(i) $A \cap B$
(ii) $A \cap C$
(iii) $\mathbf{B} \cap \mathbf{C}$
(iv) $B \cap D$
(v) $B \cap(C \cup D)$
(vi) $A \cap(B \cup C)$
Solution:
Given; A = {3, 5, 7, 9, 11}, B = {7, 9, 11, 13} and C = {11, 13, 15}, and D = {15, 17}
(i) $A \cap B=\{7,9,11\}$
(ii) $A \cap C=\{11\}$
(iii) $\mathrm{B} \cap \mathrm{C}=\{11,13\}$
(iv) $B \cap D=\Phi$ or \{\}
(v) $B \cap(C \cup D)=\{11,13\}$
(vi) $A \cap(B \cup C)=\{7,9,11\}$