Elementary problems involving time are often treated as trivial, yet they frequently conceal systematic conceptual errors. This paper analyzes two widely known examples: the classical “clock strikes” problem and the interpretation of the “first year of the Common Era”. We show that both cases rely on the same implicit confusion between counts, durations, and rates. The analysis demonstrates that seemingly obvious solutions often arise from a silent substitution of intensive quantities by ordinal indices. Clarifying this distinction resolves the ambiguity without appeal to convention or pedagogical shortcuts.
Alexey A. Nekludoff (Wed,) studied this question.