 Solution

ID: past-exam-of-the-mathematics-course-of-the-university-of-cambridge/2019/ib/paper-3/14e/b/i/solution

Codex  0 Created 2026-09-24 Updated 2026-09-29

For the sphere,

χ = 2

, and the same incidence identity gives

2 = V - \frac{E}{3}, E = 3 (V - 2) .

Therefore

\overline{d} = \frac{2 E}{V} = 6 - \frac{12}{V} < 6 .

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