# Three friends

Question: 4

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 people can safely get to their destination?

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C

A

P

T

A

I

N

I

N

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E

R

V

I

E

W

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Solution: The “aha!” factor is to understand that two of the hikers basically serve as food bearers to extend the range of the third hiker.

Call the hikers Tom, Dick, and Harry. Each hiker starts out with a four-day supply of food and water. After the first day, Tom gives a one-day supply to both Dick and Harry. This leaves Tom with a one-day supply to return to the starting point. Now Dick and Harry each have a four-day supply again. After the second day, Dick gives Harry 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 Harry a four-day supply of food and water, sufficient for the four days remaining on his journey.

Answer: One hiker can make it.