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If S denote the sum to infinity and S_n the sum of n terms of the series 1+ 1 3 + 1 9 + 1 27 + such that S-S_n 1 300 , then the least value of n is

Options

  1. A4
  2. B5
  3. C6
  4. D7

Correct answer

C. 6

Step-by-step solution

aligned & S-S_n 1 300 & 1 1- 1 3 - 1- 1 3^n 1- 1 3 1 300 3 2 [1-1+ 1 3^n ] 1 300 & 1 3^n 1 300 2 3 1 3^n 1 450 3^n 450 & Least value of n=6 aligned

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