3 men and 3 ghosts are there on one side of river(say side1) and they have to reach another side of river(say side2).
And
1. There is only one boat.
2. The capacity of boat is two members at a time.
3. At any side of the river, if number of ghosts is greater than number of men, then the ghosts will eat the men.
How could they reach safely?
Initially at
Side1: 3 ghosts and 3 men
Side2: none
Step1: First send 2 ghosts to another side.
Side1 : 1 ghost and 3 men
Side2 : 2 ghost
Step2: Send back one ghost to side1.
Side1: 2 ghosts and 3 men.
Side2: 1 ghost.
Step3: Send 2 ghosts to Side2
Side1: 3 men
Side2: 3 ghosts
Step4: Send back 2 ghosts to Side1
Side1: 2 ghost and 3 men
Side2: 1 ghosts
Step5: Send 2 men to Side2
Side1: 1 ghost and 1 man
Side2: 2 ghosts and 2 men
Step6: Send back 1 ghost and a man to Side1
Side1: 2 ghost and 2 men
Side2: 1 ghost and a man
Step7: Send 2 men to Side2.
Side1: 2 ghosts
Side2: 1 ghosts and 3 men
Step8: Send back 1 ghost to Side1
Side1: 3 ghosts
Side2: 3 men
Step9: Send 2 ghosts to Side2
Side1: 1 ghost
Side2: 2 ghost and 3 men
Step10: Send back 1 ghost to Side1
Side1: 2 ghosts
Side2: 1 ghost and 3 men
Step11: Send 2 ghost to Side2
Side1: none
Side2: 3 ghosts and 3 men