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JAMB Mathematics 1995 Question 23

Question 23

Progressions

Find the sum to infinity of the following sequence: 1, 9/10, (9/10)2, (9/10)3

  1. A.1/10
  2. B.9/10
  3. C.10/9
  4. D.10
Show the answer and explanation

Answer: D (10)

Explanation

This is a GP with a = 1 and r = 9/10. Sum to infinity = a/(1 − r) = 1/(1/10) = 10.