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.
Practise Edexcel A Level Maths Sequences and Series with exam-style questions for A Level Maths. 100 questions covering 3.1 Arithmetic Sequences, 3.2 Arithmetic Series, 3.3 Geometric Sequences, 3.4 Geometric Series, 3.5 Sum to Infinity, 3.6 Sigma Notation, 3.7 Recurrence Relations, and 3.8 Modelling with Series, matched to the Edexcel A Level Maths (9MA0) specification and written in Paper 1, Paper 2 and Paper 3 style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.