Three friends are hiking to a remote destination in a wilderness area.
The hike takes six days. Each person can carry only enough food and water for four days.
Without sacrificing anyone or endangering anyone’s life, the goal is to get as many people as possible safely to the destination.
How many hiker can safely get to their destination?
Each hiker starts out with a four-day supply of food and water.
After the first day, the first hiker gives a one-day supply to both the second hiker and the third hiker.
This leaves first hiker with a one-day supply to return to the starting point.
Now second hiker and third hiker each have a four-day supply again.
After the second day, second hiker gives third hiker a one-day supply and keeps a two-day supply for himself so that he can get safely back to the starting point.
This gives third hiker a four-day supply of food and water, sufficient for the four days remaining on his journey.
Thus, the answer is that only 1 hiker can finish the journey. 🙂