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I have been given a guide on how to reach satisfaction, and part of this guide requires me to meditate exactly for 90 minutes.
I have only been provided 2 oil-soaked ropes which last for 2 hours each when lit, and matches. (To time myself with)
I don't have a knife on me, and I am too weak to break it with my hands.
How can I meditate for exactly 90 minutes?
(Note: If you have seen a similar variation of this please don't answer)