You are at a river. With you are a Chicken, Bag of Grain, and a Wolf.
You have to cross the river in your canoe but can only take one with you at a time.
You can't leave the chicken with the grain. He'll eat it.
You can't leave the wolf with the chicken. He'll eat it.
How do you get everything over and intact?
Take the Chicken over first and leave it on the other side.
Next, take the Wolf across and leave him, but bring the Chicken back with you.
Next trip, leave the Chicken where you started and take the Grain across with the Wolf.
Finally, go back and get the Chicken.