Burning ropes Puzzle: You have two ropes and a lighter. Each rope takes exactly 60 minutes to burn completely. Given ropes burn inconsistently (for example, if you light it at one end, the first half of the rope may burn in 5 minutes while the second half may take 55 minutes).
how do you measure exactly 45 minutes?
Solution:
Two burning ropes riddle is little tricky but simple.
Take one rope and burn it at both ends. At the same time, burn one end of the other rope.
When the first rope finishes burning (i.e. 30 minutes), light the other end of the remaining rope (half of the remaining 30 minutes gives you 15 minutes)
When it burns out, that`s 45 minutes.