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WAEC Mathematics 2025 Question 27

Question 27

Progressions

The third and ninth terms of an Arithmetic Progression (AP) are 9 and −27 respectively. Find the fifth term.

  1. A.18
  2. B.3
  3. C.−3
  4. D.−6
Show the answer and explanation

Answer: C (−3)

Explanation

6d = −27 − 9 = −36, so d = −6 and a = 21. T5 = 21 + 4(−6) = −3.