A farmer must transport a fox, a chicken, and a bag of grain across a river. The boat can only carry the farmer and one item. If left alone, the fox will eat the chicken, and the chicken will eat the grain. How does the farmer get everything across?
Hints
Make multiple round trips and think about what can be left together.
Answer
1) Take chicken across. 2) Return alone. 3) Take fox across. 4) Bring chicken back. 5) Take grain across. 6) Return alone. 7) Take chicken across. This ensures fox and chicken, and chicken and grain are never alone together.