Hi there, I have really struggled to come to grips with ratios within numeracy tests. For example :

A company profit and loss account contains the following operating costs: infrastructure 2.1 million; transport 2.8 million and salaries 7.7 million. What is the ratio between the operating costs for infrastructure, transport and salaries.

Answer is 3: 4: 11 . How mathematically can one reach this answer?

Another example which I know is much simpler is:
A company's costs are $48,000 in sales and $64,000 is marketing. What is the ratio of sales to marketing costs?
Answer 3:4

Any help on how to reach these answers (or on how to work out ratios in numeracy tests in general) would be really appreciated.
Thanks