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The sum of first 20 terms of the sequence 0.7, 0.77, 0.777, ...., is -

1. 81 7 (179 + 10 –20 )
2. 9 7 (99 + 10 –20 )
3. 81 7 (179 – 10 –20 )
4. 9 7 (99 – 10 –20 )

Correct answer: 81 7 (179 + 10 –20 )

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