A geometric series has first term 5 and common ratio 45\displaystyle \frac{4}{5}54.
Calculate
the 20th term of the series, to 3 decimal places,
the sum to infinity of the series.
Given that the sum to k k\,k terms of the series is greater than 24.95, show that k>log0.002log0.8\displaystyle k > \frac{\log 0.002}{\log 0.8}k>log0.8log0.002,
find the smallest possible value of kkk.
9 exam-style questions on Edexcel A Level Old Maths Sequences and Series. Each one has a worked solution and a mark scheme showing where the marks go.