If n(A) = 115, n(B) = 326, n(A

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Target Exam

CUET

Subject

-- Mathematics - Section B1

Chapter

Relations and Functions

Question:

If n(A) = 115, n(B) = 326, n(A – B) = 47, then n A ∪ B is equal to

Options:

373

165

370

None of these

Correct Answer:

373

Explanation:

n(A) = n(A – B) + n(A ∩ B) implies

115 = 47 + n(A ∩ B)

∴ n(A ∩ B) = 115 − 47 = 68

∴ n(A ∪ B) = n(A) + n(B) − n(A ∩ B) = 115 + 326 - 68 = 373