This is one of the classical puzzles with measuring time using ropes. Can you solve this brain teaser?
Ropes
You have two ropes. Each of them burns for one hour. They burn unevenly in different parts though – it means that one half can burn for 20 minutes and other half for 40 minutes. In addition you have a box of matches.
Measure 15 minutes!
Hint
Try to figure out how to measure half an hour with one rope. The rope doesn’t divide into smaller pieces but it is not a completely wrong idea.
Answer
When you light a rope from both ends it burns in half an hour.
You only need to light both ends of one rope and one end of the other. When the first burns out you light the second end of second rope. Half hour is burned away from that one already. The rest burns out in 15 minutes, burning from both ends.
