JAMB 1992 · UME · Q9

If U={0,2,3,6,7,8,9,10}U = \{0, 2, 3, 6, 7, 8, 9, 10\} is the universal set, E={0,4,6,8}E = \{0, 4, 6, 8\} and F={x:x2=26,x is odd}F = \{x : x^2 = 2^6, x \text{ is odd}\}, find (E∩F)′(E \cap F)', where ′' means the complement of a set.

Worked solution (try it first)
  1. x2=26=64x^2 = 2^6 = 64 gives x=8x = 8 or x=−8x = -8.
  2. Neither is odd, so F=∅F = \varnothing.
  3. Nothing is in both EE and an empty set, so E∩F=∅E \cap F = \varnothing.
  4. The complement of the empty set is everything in the universal set: (E∩F)′=U(E \cap F)' = U, option B.

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