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Let S _n denote the sum of first n terms of an AP and 3 ~S _n= S _ 2 n . What is S _ 3 n : S _n equal to?

Options

  1. A4: 1
  2. B6: 1
  3. C8: 1
  4. D10: 1

Correct answer

B. 6: 1

Step-by-step solution

Given relation implies array rlrl 2 a & =(n+1) d & ~S _ 3 n ~S _n & =3 [ 2 a+(3 n-1) d 2 a+(n-1) d ]=3 2=6 array S _ 3 n : S _n=6: 1

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