Puzzle: Suppose there are 4 people and they want to pass through a bridge. Only 2 people can go through a bridge at a time and they can travel through a bridge only with a torch and they have only one torch with themselves. Find the minimum time required to pass the bridge by four of them. 1st person takes 1 min, 2nd takes 2 min, 3rd takes 5 min, 4th takes 10 min.

Puzzle: Suppose there are 4 people and they want to pass through a bridge. Only 2 people can go through a bridge at a time and they can travel through a bridge only with a torch and they have only one torch with themselves. Find the minimum time required to pass the bridge by four of them. 1st person takes 1 min, 2nd takes 2 min, 3rd takes 5 min, 4th takes 10 min.