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WAEC Further Mathematics 2021 Question 28

Question 28

Sequences and Series

The common ratio of a Geometric Progression (G.P.) is 2. If the 5th term is greater than the first term by 45, find the sum of the first five terms.

  1. A.32
  2. B.48
  3. C.93
  4. D.96
Show the answer and explanation

Answer: C (93)

Explanation

16a = a + 45 gives a = 3. S₅ = 3(2⁵ − 1) = 93.