You two minutes to find a way to count 45 seconds by having

回答: 舊文:「話說日晷」(關東行者)關東行者2024-02-13 19:17:38

a piece of stick, a pack of matches, and a knife. 

Here are a thin wood stick with the consistent burning rate, a pack of matches to burn the stick, and a sharp utility knife to cut the stick if necessary. We know it will take exactly one minute for burning the stick completely. Assuming human reaction time in fraction of second that can be negligible, can you calculate 45 seconds by using this stick with the given matches and knife?

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