Alexander is stranded on an island covered in forest.
One day, when the wind is blowing from the west, lightning strikes the west end of the island and sets fire to the forest. The fire is very violent, burning everything in its path, and without intervention the fire will burn the whole island, killing the man in the process.
There are cliffs around the island, so he cannot jump off. How can the Alexander survive the fire? (There are no buckets or any other means to put out the fire)
Alexander picks up a piece of wood and lights it from the fire on the west end of the island. He then quickly carries it near the east end of he island and starts a new fire. The wind will cause that fire to burn out the eastern end and he can then shelter in the burnt area. Alexander survives the fire, but dies of starvation, with all the food in the forest burnt.
100 people are standing in a circle. The person standing at number 1 is having a sword. He kills the person next to him with the sword and then gives the sword to the third person. This process is carried out till there is just one person left. Which number survives at the last?
73rd person will survive at last.
If the number of players is the power of 2, the last person to survive will be the one who started it.
But since the number here is not the power of 2, we will take the greatest power of 2 that is less than the number of players (100) which is 64.
So when starting with 100 players - we need to kill 36 of them to get down to a power of 2 (64). Since we kill every other person starting at player 2 the last person we need to die is player 72, they will be killed by player 71 and the first person in the effective power of 2 game, who will win is player 73.
It's worth noting that this process of reducing to a power of 2 will always be completed in the first round regardless of the number of players.
Consider X players, let Y be the highest power of 2 that is less than or equal to Y
The winning player is 2 * (X - Y) + 1
An American, who had never been to any country other than the United States, travelled a long way to see a sight that very few people had seen. He was standing one day on solid ground when he saw the Great Wall of China with his own eyes. How come?
He was an astronaut standing on the moon - from where the Great Wall of China is visible.