Multiple choice

Find the number of terms of the series 1/27, 1/9, 1/3,... 729.

  1. 10

  2. 11

  3. 12

  4. 13
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A Correct answer
Explanation

This is a geometric progression with a = 1/27 and r = 3. The n-th term is a * r^(n-1) = 729. (1/27) * 3^(n-1) = 729. 3^(n-1) = 729 * 27 = 3^6 * 3^3 = 3^9. n - 1 = 9, so n = 10.

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