Well, when I'm faced with a difficult problem, I find it helpful to go back and carefully read every word of the problem text and parse out as much information as possible. Let's do that and see what we find.
Alright. So now we know x = y.
If x and y represent the volumes of the full containers, then what expression represents "four-fifths full?"
Four liters are taken from container x, so what expression represents its new volume? That four liters are added to container y, so what expression represents its new volume?
What equation can you create that represents that the ratio of the volume in container x to the volume in container y is 2:3?
Give it a try, and see how far you get. If you get stuck again, that's alright, but when you reply back please share with us any and all work you've done on this problem, even the parts you know for sure are wrong. Thank you.