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NCERT Class XI Mathematics - Sets - Solutions
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Question : 36 of 73
Marks:
+1,
-0
If A = {3, 5, 7, 9, 11}, B = {7, 9, 11, 13}, C = {11, 13, 15} and D = {15, 17}; find (i) A ∩ B (ii) B ∩ C (iii) A ∩ C ∩ D (iv) A ∩ C (v) B ∩ D (vi) A ∩ (B ∪ C) (vii) A ∩ D (viii) A ∩ (B ∪ D) (ix) (A ∩ B) ∩ (B ∪ C) (x) (A ∪ D) ∩ (B ∪ C)
Solution:
Here A = {3, 5, 7, 9, 11}, B = {7, 9, 11, 13}, C = {11, 13, 15} and D = {15, 17} (i) A ∩ B = {3, 5, 7, 9, 11} ∩ {7, 9, 11, 13} = {7, 9, 11} (ii) B ∩ C = {7, 9, 11, 13} ∩ {11, 13, 15} = {11, 13} (iii) A ∩ C ∩ D = {3, 5, 7, 9, 11} ∩ {11, 13, 15} ∩ {15, 17} = ϕ (iv) A ∩ C = {3, 5, 7, 9, 11} ∩ {11, 13, 15} = {11} (v) B ∩ D = {7, 9, 11, 13} ∩ {15, 17} = ϕ (vi) A ∩ (B ∪ C) = {3, 5, 7, 9, 11} ∩ ({7, 9, 11, 13} ∪ {11, 13, 15}) = {7, 9, 11} (vii) A ∩ D = {3, 5, 7, 9, 11} ∩ {15, 17} = ϕ (viii) A ∩ (B ∪ D) = {3, 5, 7, 9, 11} ∩ ({7, 9, 11, 13} ∪ {15, 17}) = {3, 5, 7, 9, 11} ∩ {7, 9, 11, 13, 15, 17} = {7, 9, 11}. (ix) (A ∩ B) ∩ (B ∪ C) = ({3, 5, 7, 9, 11} ∩ {7, 9, 11, 13}) ∩ ({7, 9, 11, 13} ∪ {11, 13, 15}) = {7, 9, 11} ∩ {7, 9, 11, 13, 15} = {7, 9, 11} (x) (A ∪ D) ∩ (B ∪ C) = ({3, 5, 7, 9, 11} ∪ {15, 17}) ∩ ({7, 9, 11, 13} ∪{11, 13, 15}) = {3, 5, 7, 9, 11, 15, 17} ∩ {7, 9, 11, 13, 15} = {7, 9, 11, 15}.
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