Monday Braintease - Two ropes

Good morning monkeys. Its Monday and time to get your brain back into the swing of things. Silver bananas for whoever gets the correct answer first as well as those who explain the thought process to get the right answer well.

You have two ropes, each of which takes 1 hour to burn. But either rope has different densities at different points, so there's no gaurantee of consistency in the time it takes different sections within the rope to burn. How do you use the two ropes to measure 45 minutes?

 
Best Response

Seeing as how both ropes take exactly 1 hour to burn, lighting the rope on both ends would cause the rope to burn completely in 30 minutes. Light the first rope on both ends, while lighting the second rope on one end only. When the rope that was lit on both ends has completely burned out, 30 minutes will have passed and the second rope still has 30 minutes left to burn completely. That rope can be lit on the other end in order to cut that 30 minutes in half and get 15 more minutes total. 30 minutes for the first rope plus 15 more minutes for the second rope = 45 minutes total.

 

Seeing as how both ropes take exactly 1 hour to burn, lighting the rope on both ends would cause the rope to burn completely in 30 minutes. Light the first rope on both ends, while lighting the second rope on one end only. When the rope that was lit on both ends has completely burned out, 30 minutes will have passed and the second rope still has 30 minutes left to burn completely. That rope can be lit on the other end in order to cut that 30 minutes in half and get 15 more minutes total. 30 minutes for the first rope plus 15 more minutes for the second rope = 45 minutes total.

SB For me please

I eat success for breakfast...with skim milk
 

Looks like those two guys had a cheeky little Google.

"After you work on Wall Street it’s a choice, would you rather work at McDonalds or on the sell-side? I would choose McDonalds over the sell-side.” - David Tepper
 

Seeing as how both ropes take exactly 1 hour to burn, lighting the rope on both ends would cause the rope to burn completely in 30 minutes. Light the first rope on both ends, while lighting the second rope on one end only. When the rope that was lit on both ends has completely burned out, 30 minutes will have passed and the second rope still has 30 minutes left to burn completely. That rope can be lit on the other end in order to cut that 30 minutes in half and get 15 more minutes total. 30 minutes for the first rope plus 15 more minutes for the second rope = 45 minutes total.

 
patpat:
Seeing as how both ropes take exactly 1 hour to burn, lighting the rope on both ends would cause the rope to burn completely in 30 minutes. Light the first rope on both ends, while lighting the second rope on one end only. When the rope that was lit on both ends has completely burned out, 30 minutes will have passed and the second rope still has 30 minutes left to burn completely. That rope can be lit on the other end in order to cut that 30 minutes in half and get 15 more minutes total. 30 minutes for the first rope plus 15 more minutes for the second rope = 45 minutes total.

cheater

I eat success for breakfast...with skim milk
 
melvvvar:
i only need one rope. i shred the rope completely and reconstitute it such that it is of even consistency. burn it til 3/4 is left.

now that is some divergent thinking. SB for moi.

poop from me

I eat success for breakfast...with skim milk
 
TonyPerkis:
melvvvar:
i only need one rope. i shred the rope completely and reconstitute it such that it is of even consistency. burn it til 3/4 is left.

now that is some divergent thinking. SB for moi.

poop from me

i use the other rope for autoerotic asphyxiation.

 
Anacott_CEO:
You're all right, it wouldn't be hard to cheat, but it's also not hard to remember feedback from previous interviews. Seeing as how I am not a very abstract thinker, I got this question and another question about angle of clock hands wrong previously.

The clock one isn't really abstract thinking though it is. This rope one, I would say, is.

"After you work on Wall Street it’s a choice, would you rather work at McDonalds or on the sell-side? I would choose McDonalds over the sell-side.” - David Tepper
 
Anacott_CEO:
You're all right, it wouldn't be hard to cheat, but it's also not hard to remember feedback from previous interviews. Seeing as how I am not a very abstract thinker, I got this question and another question about angle of clock hands wrong previously.

The clock one is good. I first though 0 degrees.

 

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