WAEC Further Mathematics 2006 Question 1

Question 1

Sets and Logic

If P = {x : 1 ≤ x ≤ 6} and Q = {x : 2 < x < 9}, where x ∈ R, find P ∩ Q.

  1. A.{x : 2 ≤ x ≤ 6}
  2. B.{x : 2 ≤ x < 6}
  3. C.{x : 2 < x < 6}
  4. D.{x : 2 < x ≤ 6}
Show the answer and explanation

Answer: D ({x : 2 < x ≤ 6})

Explanation

The intersection keeps the numbers in both sets: they must be greater than 2 (from Q) and at most 6 (from P), so P ∩ Q = {x : 2 < x ≤ 6}.