Two ropes that each burn for an hour, unevenly, and a lighter: time exactly 45 minutes.

Two ropes that each take 60 minutes to burn end to end, but unevenly, and a lighter. The story asks how to time exactly 45 minutes. You pick one of four answers. Then you step through the answer and the breakdown.

Why quant interviews test this

Interviewers want you to rule out length straight away and state the both-ends fact before using it. The written solution is at /brain-teasers/burning-ropes/solution.

The The Burning Ropes guide covers how scoring works, the strategy that wins, a worked example and the mistakes most players make.

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