Define:

[Math]I_1,I_2[/tex] Incomes of person 1 and 2

[Math]E_1,E_2[/tex] Expenditure of persons 1 and 2.

You are given the following ratios:

This is 3 equations in 4 unknowns, so we can choose one of the values. I will set

Now:

You should be able to solve that system of simultaneous equations to get

The ratio you want is

Its interesting to note that the savings amount comes out as negative for both people...but thats another story.

If you are interested inwhyi can set without breaking the answer, its because we are only interested in ratios, not the actual levels of income. I am effectively redefining the currency unit of the problem so that has 1 unit.