Watch the video: Logic puzzle “The burning ropes” – can you solve this puzzle?
The “Burning Ropes” is a classic logic puzzle. Basis: We have two ropes that each take an hour to burn, but they don’t burn at the same rate.
How can you measure 45 minutes using the burning ropes?
It is permitted to light one or both ropes at one or both ends.
The problem: Since both ropes burn at different rates, we cannot simply light one end of a rope on fire and wait until it is 75 percent burned out.
But we can do this: we light the first rope at both ends and at the same time light the other rope at only one end.
The first rope takes 30 minutes for the two flames to meet. At this very moment we light the other end of the second rope. Since the burning time of the second rope was 30 minutes so far, it takes exactly 15 minutes for the two flames to meet. In total, the second rope burned for exactly 45 minutes.