In a geometric progression, the second term is 4 and the sum of all terms is 25.
Find the two possible values of the common ratio rrr.
Find the corresponding two possible values of the first term aaa.
Given that r r\,r takes the larger of the two possible values, find the smallest value of n n\,n for which Sn>24.5S_n > 24.5Sn>24.5.
308 exam-style questions on AQA A Level Maths 1.7 D: Sequences and series, covering 1.7.1 Binomial expansion, 1.7.2 Types of sequence (A-level only), 1.7.3 Sigma notation (A-level only), 1.7.4 Arithmetic sequences and series (A-level only), 1.7.5 Geometric sequences and series (A-level only), and 1.7.6 Sequences and series in modelling (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.