How do we measure forty-five minutes using two identical wires, each of which takes an hour to burn? We have matchsticks with us. The wires burn non-uniformly. So, for example, the two halves of wire might burn in 10 minutes and 50 minutes respectively.
Puzzle 1 | (How to Measure 45 minutes using two identical wires?)
Answer: If we light a stick, it takes 60 minutes to burn completely. What if we light the stick from both sides? It will take exactly half the original time, i.e. 30 minutes to burn completely.
1. 0 minutes – Light stick 1 on both sides and stick 2 on one side.
Puzzle 1 | (How to Measure 45 minutes using two identical wires?)
2. 30 minutes – Stick 1 will be burnt out. Light the other end of the stick 2.
Puzzle 1 | (How to Measure 45 minutes using two identical wires?)
45 minutes – Stick 2 will be burnt out. Thus 45 minutes is completely measured.