I have a two piece of rope both 1m long that I know take exaclty 1 hour each to burn if lit from one end. I am locked in a room and have a lighter and need to measure out 45 minutes exactly to escape out. However, the ropes burn at different rates i.e. one rope could take 10 minutes to burn the first 50cm of the rope and 50 minutes to burn the last 50cm, whilst the other rope could burn the first 50cm in 25 minutes and the last 50cm in 35 minutes. How do I measure out the 45 minutes exactly?
