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WAEC Mathematics 1997 Question 4

Question 4

Sets

A and B are two sets. The number of elements in A∪B is 49, the number in A is 22 and number in B is 34. How many elements are in A∩B?

  1. A.105
  2. B.27
  3. C.15
  4. D.12
  5. E.7
Show the answer and explanation

Answer: E (7)

Explanation

n(A∩B) = n(A) + n(B) − n(A∪B) = 22 + 34 − 49 = 7.