Liam starts a training program where he runs 150 km in the first month and increases his monthly distance by 25 km each subsequent month. Sarah also starts a training program; she runs 210 km in the first month and increases her monthly distance by 15 km each subsequent month.
After how many months have Liam and Sarah run the same total distance.
20 exam-style questions on Edexcel A Level Maths 3.8 Modelling with Series. Each one has a worked solution and a mark scheme showing where the marks go.