Listen to the full episode here:
http://www.blogtalkradio.com/thebiggamehunter/2017/04/12/the-two-ropes-brainteaser
Ep 713 Jeff Altman, The Big Game Hunter discusses one of those tough hedge fund brainteaser questions, the two ropes problem.
Today, I want to pose what for some of you are frustrating and for others of you annoying hedge fund brainteaser questions and provide you with the answer for it. Today's question deals with this scenario--you have 2 ropes and a lighter. You'll be asked to measure out 45 minutes BUT the ropes can burn at varying speeds. So, for example, one rope might burn halfway in 5 minutes and the other in the remaining 55. You don't know which is which. You just know that you have to measure out 45 minutes with these 2 ropes in a lighter. How do you go about doing it? One rope (let's call it Rope A) you light at both ends. Rope B only light at one end. At the end of 30 minutes, the 1st rope is going to be done. Now with the 2nd rope lighting at the other end so that now both ends are burning. By the time that one is exhausted, 15 minutes has elapsed. That's how you're going to measure out 45 minutes of time. Just repeat, the 1st rope is lit at both ends; the 2nd rope 1 end. After 30 minutes, the 1st rope is gone. Now light the 2nd rope from the 2nd end , and 15 more minutes has gone by.