Q. There are 2 equal length string in a dark room, you have a lighter, each string can burn up completely in 1 hr, there is no clock in the room.
Here is the question, you need to come out of room by 45Mins, how will you come out?

• burn one string from one end and other one from both the ends.
  by doing so, second one will burn completely in 30 mins. and first one will burn to half its length.
  when second one will burn completely then burn the first one from other end as well. now the remaining string will burn in 15 mins.when it is burnt completely 45 mins(30+15) are completed.
• 11 years agoHelpfull: Yes(2) No(0)
• lit both sides of a string and one side of the other..
  after 30mins one will be completly burnt and the other will last a half...now lit the string remaining on the other side also....it will complete in 15 mins.. so,totally 45 mins is over.!
  
• 10 years agoHelpfull: Yes(0) No(0)