Lateral Thinking · Ages 10–12
Riddle #96
You have two ropes and a lighter. Each rope takes exactly 60 minutes to burn all the way through, but they burn unevenly — some parts fast, some parts slow. How can you measure exactly 45 minutes?
You solved this one before
Open-ended riddle: think it through, then reveal the answer.
Answer: Light one rope at both ends and the other rope at one end, all at the same time. The first rope finishes in 30 minutes (the two flames meet in the middle). The instant it finishes, light the second rope's other end too — now it burns from both ends and finishes in the remaining 15 minutes.
30 minutes + 15 minutes = 45 minutes total.