Say I have a data set in the following format: {a:200, b: 100; c:400}
The sum of a, b and c equals 700. Now, I have another value which is supposed to be the actual total say 500.
How do I adjust this difference of 200 in the initial data set (the values for a, b and c must be proportionately decreased summing 200 - something like a weighted difference)?