Brain Teasers & Mental Math
The burning-rope puzzle: you have two ropes, each burns in exactly 60 minutes but unevenly (rate varies along the rope). Using only these ropes and matches, how do you measure exactly 45 minutes?
Model answer
Light rope A at BOTH ends and rope B at ONE end simultaneously.
Rope A burns from both ends and meets in the middle after exactly 30 minutes (two flames consume the whole 60-minute rope twice as…
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