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COMEDK202510 May 2025Morning ShiftMathematicsSets and RelationsActual

If n(A)=3 and n(B)=7 and A B then the number of elements in A B is equal to

Options

  1. A0
  2. B7
  3. C3
  4. D10

Correct answer

C. 3

Step-by-step solution

Given that A B , every element of set A is also an element of set B . By definition of intersection, A B = x : x A and x B . Since A B , for any x A , it follows that x B . Therefore, A B = A . The number of elements in A B is equal to n(A B) = n(A) . Given n(A) = 3 , it follows that n(A B) = 3 . Answer: 3

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