Plz, help me with this question. Do plz show me how to do it and the calculations as well.

As the managing partner of Crane Accounting Services (HAS), Adam is trying to compare the profitability results of the firm's three different business lines: Audit, Tax, and Advisory Services. These three operating divisions are supported by three support departments: Billing, Human Resources, and IT. The cost drivers (or allocation bases) for each of the support departments, along with each department's usage of those services and its own original costs, are as follows. (a) Rank the three support departments by their original costs, and then allocate the support department costs using the step method. (Round intermediate calculations to 4 decimal places, e.g. 15.2516 and final answers to 2 decimal places, e.g. 15.25.)