I've got some of these mixing cups
Quite clever. Take a 2:1 mix. You fill the cup with A up to the level, say, of the 5 in the LH column. Then add B to bring the total level up to the 5 in the RH column. (A:B = 2:1).
But what about those smaller graduations ? 5,10, 15 etc. What are those for ?