82. There is a water tap and two containers: a three-liter and a five-liter. How can you get 4 liters of water in the larger one?
82. Let's fill a five-liter container and pour 3 liters from it into a three-liter container. Then we will empty the three-liter container and transfer the 2 liters of water remaining in the five-liter container into it. Finally, we will fill the five-liter container from the tap and pour 1 liter from it into the three-liter container. Now we will have 4 liters of water in the five-liter container.