Surviving the Technical Interview Page 4
Answer to the Fox and Chicken Dilemma
The answer to the fox and chicken dilemma is really very simple, but many people puzzle over it endlessly because of their one-way mode of thinking. Here's the solution:
The man takes the chicken across first, leaving fox and grain together on the other side. He returns and gets the fox, but when he deposits the fox on the other side, he takes the chicken BACK across, so that the fox and chicken aren't left alone together. He drops the chicken off back on the other side, picks up the grain, and takes it across to deposit with the fox.
Finally, he returns to retrieve the chicken and takes it to the other side.
At no time were the fox and chicken left alone together, nor were the chicken and grain.
At no time was more than one of them in the boat with the man simultaneously.
The reason this puzzle is so difficult for many people is that it never occurs to them that they can take something back once they've transported it to the second side. Your ability to solve this puzzle demonstrates a willingness to think "outside the box" and come up with creative solutions that still fit within the specified parameters.
Revised, Dec. 20, 2010