https://www.sarthaks.com/183043/the-sum-of-first-20-terms-of-the-sequence-0-7-0-77-0-777-is
or
https://learn.careers360.com/engineering/question-try-this-the-sum-of-first-20-terms-of-the-sequence-07-0770777is/
or
https://doubtnut.com/question-answer/the-sum-of-first-20-terms-20-terms-of-the-sequence-070770777-is-53796460
have the solutions, the answere tho is option 4 which is \((7/81)(179 + 10^{-20})\)
