You are alone in a room. You are given multiple number of candles. You have no measuring aids with you. You have a match box with you. You have to accurately measure 45 minutes. The total time a candle takes to burn out completely is 30 minutes. How would you measure?

• This question would have had a very simple answer with something other than a candle. Something which could be burnt from both the sides, say a rope.
  However, taking that away, say you can burn the candles from both the sides, here is the solution:
  Take 2 candles.
  Light one. This would take 30 minutes.
  After it gets burnt out, burn another immediately from both the ends.
  Since the entire candle takes 30 minutes to burn, the candle being burnt from both the ends would take 15 minutes.
  At the end, 30 + 15 =45 Minutes.
  Hope this helps!
• 8 years agoHelpfull: Yes(58) No(0)
• only 2 candles are required,
  we know that, one candle takes 30 minutes to burn, if we burn the candle both side then it will take 15 minutes,after it get burnt out,burn another candle,the second candle will takes 30 minutes, so total time will be 15+30=45 minutes....
• 8 years agoHelpfull: Yes(13) No(1)
• Only 2
  30 +15 consider two candles
• 7 years agoHelpfull: Yes(1) No(0)
• light up a single candle and count the number of drops it is leaking if
  for example it leaks 100 drops = 1 candle then light up another candle after that and stop at 50 drops so total time measured up is 30min in 1st candle and 15min in second candle i hope so
• 7 years agoHelpfull: Yes(1) No(6)
• i candle full in 30 min and burn other from both sides so 2 burn in 45 mins
• 7 years agoHelpfull: Yes(0) No(0)
• burn 1 candle when it is half burnt burn an another candle. so let the both candle light and once both of them burn out you can measure 45 min
  
• 7 years agoHelpfull: Yes(0) No(1)
• what if we burn 3 candles in 45 minutes all from both end.question should be maximum or minimum no of candles can be measured like this.
  
• 7 years agoHelpfull: Yes(0) No(0)
• Lit the first candle both sides it will burn out after 15min..then lit the second one it will burn out after 30min so you'll total of 45min
• 7 years agoHelpfull: Yes(0) No(0)
• one candle takes 30 mins to burn so we can measure 45 mins like by burning one and half candle
• 7 years agoHelpfull: Yes(0) No(0)