Well using your same method I got 5:43
Let total be 1000ml
250:750 = 1:3
1000:1400 = 5:7
To calculate how much water there is we know that 750ml of that original 1000ml is water, plus add another 1400ml of water so a total of 2150 ML
There is 250 grams of sugar in the solution so 250:2150...