https://www.popularmechanics.com/science/math/a24210/solution-to-riddle-of-the-week-6/
I look at my watch?
Burn one rope at both ends, and light the second rope at one end. The first rope will burn through in a half hour and the second rope will burn halfway through. Light the remaining second rope at both ends and it will take 15 minutes to burn through.
Or just look at your watch or your phone.
I didn’t read the solution, but that kind of a brain teaser sounds like something a few fictitious famous men may have tried.
Sherlock Holmes
Sir Lawrence of Arabia
Macguyver (sp)
Clutch Cargo (OK, Boomer!)
Light both ends on the first rope. That will be 30 minutes. Fold the second rope burn the middle then light up the other ends . That will give 15 minutes.
To measure exactly 45 minutes using two ropes that each take one hour to burn completely, despite non-uniform burning rates, follow these steps:
Thus, you can measure exactly 45 minutes by timing from the initial lighting until the second rope is fully burned.
Tie both ropes together, light them on fire, and when they are 3/4 burned....
45 minutes.
(I did not look at the answer first. FWIW)
There are a lot of missing variables. BUT. Not knowing what they mean by taking “one hour to burn all the way through “ I surmise they mean lighting one end and burning like a wick. If that’s the case. Fold one robe in half and light both ends for 30 minute burn. Fold the other rope two time in half. When the 30 minute rope is finished burning light the ends on the other folded rope for a 15 minute burn.
I’ll take “with a watch”…… for $400 Alex!
I didn’t check, but how about light them after they’ve burned for 15 minutes.
One of my dad’s questions when growing up...”an electric train is going north at 30 mph while the wind is blowing south at 30 mph. Which way will you the smoke go?”
They make it sound like you are burning through the rope like in the image, not longways like a fuse. It’s early and I’m just getting my coffee.
Light both ropes.
When one rope reaches the beginning of the fourth segment and then the second rope reaches the beginning of the fourth segment, it has been 45 mins.
I have a watch.
We had a hunting cabin, that had been an old pioneer cabin, which we leased out with hunting leases. It had a handmade stone fireplace. Some city boys took the lease for the area with it and decided to make a fire in the fireplace.
They foraged and found a long cedar post, which they brought back. They put one end in the fireplace and lit it and went about their business, assuming the part of the post in the fireplace would burn in the fireplace would burn off and they could shove it in as it burned off. Soon the whole log was on fire and setting the floor on fire. They did get it out but a long track was burned into the floor. Didn’t have much water and couldn’t carry it out because it was all on fire.
Yes, there are morons that stupid among us. Maybe their mental model of burning cylindrical objects was based on cigarettes. Or “Popular Mechanics”.
The same kind of impractical morons came up with this “puzzle”, or read it and take it as useful, or think it was worth distributing. I think articles like this make stupid people stupider.
Oh and AI is that stupid. ( Thanks/HT to freeper who tried it.)
What if the ropes identify as a steel cable ?
Oh... That’s not the burning rope trick that I know... And you don’t want to.