OK, here ya go. There is a farmer with a fox, a duck, and a bag of grain. He has 1 boat, and he must get them all across the river, IN THE BOAT, and he can only carry them one at a time. Now think, he can't leave the duck and the fox together, and he can't leave the duck and the grain together. How does he transport them.

Duck,
back empty
fox
duck back
grain
back empty
duck

right?

take the duck across first
pick up the fox next pass
take fox across, pick up the duck and carry it back
pick up grain and drop off duck
take grain across
take duck acorss

Yup.