You have two candles, each one of which can burn for an hour. How will you burn the candles to measure a time equal to a quarter less than an hour?
Light the 1st candle at both the ends and the 2nd one at one end only.
Now, in 30 minutes, the 1st candle which was burning at both ends is completely burned out.
Now light the 2nd candle (which is still burning at one end) at the other end also. It is important to note here that in half hour, this candle would have burned out 50% already.
This 2nd candle will now take 15 minutes to completely burn out as it is lighted at both ends.
So, the total time taken to burn both the candles is = 30 + 15 = 45 minutes.
Now, in 30 minutes, the 1st candle which was burning at both ends is completely burned out.
Now light the 2nd candle (which is still burning at one end) at the other end also. It is important to note here that in half hour, this candle would have burned out 50% already.
This 2nd candle will now take 15 minutes to completely burn out as it is lighted at both ends.
So, the total time taken to burn both the candles is = 30 + 15 = 45 minutes.