Answer: there are 2 ways as follows

Solution 1:

Fill the 5 liter jug. Then fill the 3 liter jug to the top with water from the 5 liter jug. Now you have 2 liters of water in the 5 liter jug. Dump out the 3 liter jug and pour what's in the 5 liter jug into the 3 liter jug. Then refill the 5 liter jug, and fill up the 3 liter jug to the top. Since there were already 2 liters of water in the 3 liter jug, 1 liter is removed from the 5 liter jug, leaving 4 liters of water in the 5 liter jug. Solution 2:

Fill the 3 liter jug and pour it into the 5 liter jug. Then refill the 3 liter jug and fill up the 5 liter jug to the top. Since there were already 3 liters of water in the 5 liter jug, 2 liters of water are removed from the 3 liter jug, leaving 1 liter of water in the 3 liter jug. Then dump out the 5 liter jug and pour what's in the 3 liter jug into the 5 liter jug. Refill the 3 liter jug and pour it into the 5 liter jug. Now you have 4 liters of water in the 5 liter jug.