> have two ropes, a) and b)
> each rope burns down in exactly 60 minutes, but not necessarily in a steady manner
Measure 15 minutes of time by using the two ropes and a zippo. If you cannot do it, go to sleep immediately (source: I have a phd in severe internet retardation.)
Light one end of one rope then light the other from both sides. After the one lit from both sides has burned through, 30 mins will have elapsed. Therefore, the other rope will have 30 mins left to burn so light it from the other side and it will take 15 mins to finish off.
you are allowed to stay awake
Th-thank you s-s-senpai.
By folding one rope like this and burning only what is inside the green borders, one measures 15 minutes without destroying more than 1/4 of one rope.
>but not necessarily in a steady manner
you failed miserably.
go to sleep kohai, or commit sodoku alternatively
Cut the rope into 1/16ths. Burn one piece. You now have 15. Take the zippo and burn your little finger. Do a 360 turn while reciting the Lorentz transformations. Add 3.
Is that actually how this works? What if one centimeter of the rope burns in fifty five minutes and the rest of the rope burns in five minutes
commit sudoku
go to sleep
>after the one lit from both sides has burned through, 30 mins will have elapsed
no the rope burns down in exactly 60 minutes.
looking back at this, that's pretty elegant. how do i smart like this?
If only lit on one end.
This rope, however, has been lit from both ends, effectively doubling the burn rate
>unironically using pink guy reaction images
you should tie one of those ropes into a noose
I go to sleep boss
does internet retardation actually exist? I think I might suffer from it
Burn one; construct a pendulum from the other. Count the number of oscillations until the rope burns. Release the pendulum again for 1/4 of the oscillations counted before.
>tfw about to go to sleep anyway
Thanks for the permission anyway Boss
don't call me boss
my name is b0ss
>but not necessarily in a steady manner
Well, in that case we have a purely probabalistic system and need to work with an arithmetic mean. I put both ropes into a straight line and light them at the same time. If x_i is the length of the burned rope, then I wait until the point (x_1+x_2)/2 is reached. Set standard deviation to 3%. After reaching the defined point I will be at t=15 minutes ± 0.45 minutes.
Full retard. I meant that you have to "guess" when each rope has reached the state of being 1/4th burned. Hence standard deviation to adjust for this poor measurement.
N is only 2 and besides that you can't possibly define the standard deviation exactly.
Problem is totally unbounded thanks to
>not necessarily at a steady rate
swap zippo for a cheap watch
go to sleep, kohai
I cut one rope into about 100 or so pieces of equal length and randomly divide them into 20 groups of 5. I then light those pieces in all the groups at exactly the same time using the fuel in my zippo poured out into a small straight depression.
When 10 of the groups are burned completely, it is very very close to 15 mins.
Well yes, that's the problem. What does this unsteady rate even mean to begin with? Are the densities of both ropes homogenous, but different to each other? Is the density of each rope discontinuous? If the latter is the case, then it's impossible to accurately measure 15 minutes.
Brain fart. Meant 4 groups of 25. When 2 are burnt you are good to go.
congratulations, you invented calculus
>density
Completely extraneous. All you need to know is that the rate is I'll defined and not constant. Why it is so is unnecessary.
nall
That's not calculus you mong. It's statistics.
For double the precision, do the same thing with the other rope and average the two times.
...
It's a well known riddle that he most likely googled when he heard it the first time.
The burn rates are non-homogeneous, even within a single rope.
You didn't even read the first fucking reply. It's already got the correct answer and you're sitting here saying its impossible. Doesn't that make you feel dumb?