Given two candles that can be lit from either end. Each candle takes exactly one hour to burn completely when lit from a single end, even though it burns unevenly along its length. You also have a box of matches. Using only these candles and the matches, measure 45 minutes and 15 minutes.
Check if you were right - full answer with solution below.
Solution:
Step 1: At 0 Minutes:
Starting at the same time:
- Light Candle 1 from both ends.
- Light Candle 2 from one end only.
Step 2: At 30 Minutes:
- Candle 1 burns out completely because it is burning from both ends. This marks 30 minutes.
- By this time, Candle 2 has 30 minutes of burning time remaining, even though it has burned unevenly. Now light Candle 2 from the other end.
Step 3: At 45 Minutes:
- Since Candle 2 is now burning from both ends, its remaining 30 minutes of burning time is consumed in 15 minutes.
- When Candle 2 burns out, another 15 minutes have passed.
So, Candle 1 burning out measures the first 30 minutes, and Candle 2 burning out measures the next 15 minutes, giving a total of 45 minutes.