So, just to clarify for people like me (gave up mathematics and chemistry age 14, find ratios difficult to grasp sometimes, has to calculate the dilution on a scrap of paper each time I make up some developer) ...
10g/l = 1% solution
100g/l = 10% solution
200g/l = 20% solution ... and so on, up to the solubility limit of KBr in water I presume.
SO, when I am making up a litre of developer that requires 1g of KBr per litre, I would substitute 100ml of a 10% solution for 100ml of the total volume of water required by the formula ?
(I imagine a lot of sighing, eye rolling and shaking of heads from all the scientificky types at this point)