Multiple choice

Find the sum of 8 terms of common differences in the given sequence. 3, 6, 15, 42, 123……

  1. 10132

  2. 8452

  3. 6578

  4. 9840
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D Correct answer
Explanation

The sequence is 3, 6, 15, 42, 123. Differences are 3, 9, 27, 81. This is a geometric progression with a=3, r=3. The sum of 8 terms of the differences is 3 * (3^8 - 1) / (3 - 1) = 3 * 6560 / 2 = 9840.

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