Plant food question

Hi all. I know what kind of plant foods that I need but my question is

for the numbers like 20-20-20 , 1-1-1.5 and such do those numbers mean when they say to use say 3ml in 1L of water that you will get 20-20-20 for that water?

or does 20-20-20 mean that there is 20% of the weight of each number in the container of the plant food that the container that they are in?

no it's not 20% of the weight, it's a ratio of parts inside the fertilizer, that is 1-1-1.5 signifies 1 part N 1part P and 1.5 part K, the part could be any weight, you could usually see the label to know the exact weight of each part.