You may have met this introductory problem before, but have a think about it in preparation for tackling the main one that follows.
Once upon a time a farmer went to market and bought a fox, a hen and a sack of corn.
The farmer came to a river which needed to be crossed by boat. He could take only one of his purchases - the fox, or the hen, or the sack of corn - in the boat at a time.
Can you find a way for the farmer to get all of them across the river safely? (Note - only the farmer can row the boat!)
Can you find more than one way of getting them across with the minimum number of crossings?
Two adults and two children need to cross a river in a rowing boat. Can you determine how to get everyone across, and how many crossings are needed, given the following information?
What if there were $3$ adults and $2$ children?
What if there were $100$ adults and $2$ children?
What if there were $n$ adults and $2$ children?
If you enjoyed these problems, you may also like to take a look at Crossing the Bridge.
With thanks to Don Steward, whose ideas formed the basis of this problem.