6. The first term of a geometric series is 20 and the common ratio is \(\frac { 7 } { 8 }\)
The sum to infinity of the series is \(S _ { \infty }\)
- Find the value of \(S _ { \infty }\)
The sum to \(N\) terms of the series is \(S _ { N }\)
- Find, to 1 decimal place, the value of \(S _ { 12 }\)
- Find the smallest value of \(N\), for which
$$S _ { \infty } - S _ { N } < 0.5$$