Multiple choice

The nth term of the series is 2n - 5. Find the ratio of the sum of the first five terms to the next five terms.

  1. 1 : 11

  2. 2 : 5

  3. 1 : 2

  4. 3 : 8
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A Correct answer
Explanation

Term = 2n - 5. First 5 terms: n=1 to 5: -3, -1, 1, 3, 5. Sum = 5. Next 5 terms: n=6 to 10: 7, 9, 11, 13, 15. Sum = 55. Ratio = 5/55 = 1/11.

AI explanation

Using the nth term formula 2n - 5, the first five terms are -3, -1, 1, 3, and 5, which sum to 5. The next five terms (from the 6th to the 10th term) are 7, 9, 11, 13, and 15, which sum to 55. The required ratio of the sum of the first five terms to the next five terms is 5 to 55, which simplifies to 1 : 11.

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