Sorry I don't see a number line but I'll try to explain ; Because the ratio of flour to water is 10 to 7 and there's a total of 600 grams, you divide the 600 by 10 which then gets you 60 (this will be your constant or whatever you call it i forgot). You then multiply 7 by 60 and you will get an answer of 420 grams of water!
