Logic test

[Marineboy]

You are equipped with two ropes and some matches.

Your goal is by burning the rope(s), to identify when exactly 45 minutes has passed. All you know about the ropes is:

* The ropes are of different length and you don't know how long they are.
* Each rope burns in precisely 1 hour.
* Each rope has a non-uniform density, meaning it is thicker at some points than others. Consequently, burning half a rope cannot be guaranteed to take 30 minutes.

[Guest]

[Mike]

My head hurts

[livvy145]

It's actually not as hard as you think. Remember, you can burn a rope at both ends.

[meffin]

heres as far as i got;

burning both ends would take 30 mins to burn the whole rope
burning from one end would take 60 minutes

and thats about it...

[meffin]

count to 2700, thats 45 minutes worth of seconds

[MrsB]

Burn one rope from both ends and the other from one. As soon as the first rope is completely burnt, burn the seconed rope from both ends. Voilà.

[Marineboy]

heres as far as i got;

burning both ends would take 30 mins to burn the whole rope
burning from one end would take 60 minutes

and thats about it...

close, very close.....

[Rhys]

heres as far as i got;

burning both ends would take 30 mins to burn the whole rope


and thats about it...

then count the next 15

ive got it though

if you burn both ropes at the same time but, only light one of the ropes on one side with the other being on both. it would take 30 mins for one of the ropes to burn, then you light the other end of the other rope which will take another 15 to brun fully. and voila 45 mins

[Marineboy]

Burn one rope from both ends and the other from one. As soon as the first rope is completely burnt, burn the seconed rope from both ends. Voilà.

and we have a correct answer!

* First light rope 1 in both ends and one end of rope 2.
* After 30 minutes rope 1 is completely burnt and rope 2 still has 30 minutes worth of burning time in it.
* Light the other end of rope 2. This will burn the remaining rope in 15 minutes, totaling the burning time to 45 minutes.

[badpiggy]

i don't find this the least bit funny

[Pacman]

i don't find this the least bit funny