Moderate -0.8 This is a straightforward application of the sum to infinity formula S∞ = a/(1-r), requiring only algebraic rearrangement to solve for r given S∞=5 and a=2. It's easier than average as it's a direct one-step formula application with no conceptual challenges, though not trivial since students must recall and manipulate the formula correctly.
3 The sum to infinity of a geometric series is 5 and the first term is 2 .\\
Find the common ratio of the series.
\hfill \mbox{\textit{OCR MEI C2 Q3 [3]}}