Top Puzzle 14: The Two-Fuse Time Problem | Puzzles for Interview - Interview Preparation PDF Download

Problem Statement

In a room, there are two fuses and a burning candle. The fuses are of different lengths and burn at different rates. The shorter fuse burns completely in an hour, while the longer fuse takes two hours to burn completely. You need to measure exactly 45 minutes using these two fuses and the burning candle. How can you do it?

Solution

To measure exactly 45 minutes using these two fuses and the burning candle, follow the steps mentioned below:
1. Light both fuses from one end at the same time.
2. After 30 minutes, the shorter fuse will be completely burnt, while the longer fuse will still have half of its length remaining.
3. At this point, light the other end of the longer fuse using the candle flame.
4. The remaining half of the longer fuse will take exactly 15 minutes to burn completely.
5. When the longer fuse is completely burnt, 45 minutes will have passed since you lit both fuses.

Conclusion

The above solution demonstrates that it is possible to measure exactly 45 minutes using two fuses of different lengths and burning rates, along with a burning candle. This puzzle requires logical thinking and problem-solving skills to come up with a solution. It also highlights the importance of using available resources and creativity to solve problems effectively.