3 In this question you must show detailed reasoning.
- Write down the first 5 terms of the geometric series
$$\sum _ { r = 0 } ^ { n } 20 \times 0.5 ^ { r }$$
- Find the smallest value of \(n\) for which the series
$$\sum _ { r = 0 } ^ { n } 20 \times 0.5 ^ { r }$$
is greater than \(99.8 \%\) of its sum to infinity.
[0pt]
[5]