How to us the step down method to solve this problem

Question 23 12 pts Ballew & Ballew is a small accounting firm in Spring Valley that provides both audit and tax services. In addition to these two functional units, they have three support departments: Human Resources (HR), Administrative Staff, and Marketing. Both the Canvas.rice.edu/courses/3860 1/quizzes/4897@/take 021 Quiz Mid-lem Exam Marketing and the Admin Staff departments use the services from HR, but HR does not use Admin Staff or Marketing. The Marketing department uses admin support, but admin support does not use marketing. The functional departments use the services of all three support departments. The cost driver of the HR dept is headcount, the cost driver for the Admin Staff is the number of hours they spend supporting marketing, audit or tax professionals, and the cost driver for the marketing department is the number of clients in each functional unit. The following table provides relevant data: Service consumed by: Admin HR Marketing Audit Tax Total Staff Costs $160,000 $120,000 $85,000 $5,000,000 $4,500,000 $9,865,000 incurred Service provided by HR (head 2 3 15 10 29 count) Admin Staff 600 3300 2900 6800 (hours) Marketing (# 55 110 165 of clients) Number of 35,000 23,000 58000 billable hours The Audit department expects to bill their clients 35,000 hours of audit work, and the tax department expects to bill 23,000 of tax work. Allocate the support department costs to the audit and tax departments using the step-down method starting with HR, then Admin Staff, and last the Marketing Calculate the hourly billable rates for the two functional units, Audit and Tax