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If the sum of the first (2 n ) terms of (2,5,8, ) is equal to the sum of the first (n ) terms of 57,59 , (61 ). , then ( n ) is equal to

Options

  1. A10
  2. B12
  3. C11
  4. D13

Correct answer

C. 11

Step-by-step solution

Given, ( 2 n 2 2.2+(2 n-1) 3 = n 2 2.57+(n-1) 2 ) or (2(6 n+1)=112+2 n ) or (10 n=110, ~ n=11 )

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