Charlie is training to run a marathon. Each week he goes for a long run. In Charlie's first long run he runs 10 km. He then increases the length of his run by 2 km each week. A marathon is 42 km.
Find the number of weeks it takes until Charlie runs a full marathon.
Find the number of weeks until the total length of Charlie's long runs exceeds 200 km.
178 exam-style questions on Edexcel A Level Maths Sequences and Series, 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. Each one has a worked solution and a mark scheme showing where the marks go.