Sunday, May 15, 2011

Counting 45 minutes


There are two pieces of identical ropes. If one burns a rope from one end, it takes an hour to completely burn the whole rope. However, the materials that make up the rope are not even. In other words, if one cut the rope into two equal halves, it does not necessarily takes half an hour to completely burn one of the halves. 


Now, you are asked to count 45 minutes, but you do not have any clock or watch. How would you do so by using these two pieces of ropes and matches?