LO6.7 Bairstow Consulting Lid offers a range of IT consulting services. The company's service costing system 6.8 estimates the cost of each consulting job by accumulating costs of the professional labour that works on the job plus a charge for overhead. The cost of professional labour is charged to jobs using the following three rates: IT trainee $ 30 per hour IT graduate $ 75 per hour IT senior consultant $225 per hour The predetermined overhead rate is based on professional labour costs, which are budgeted to be $663 600 for the current year. The estimated overhead costs for the current year are budgeted to be: Management salaries $735 000 Salaries of clerical and reception staff 285 000 Depreciation on IT hardware and software 240 000 Stationery 22 500 Telecommunications 31 500 Insurance 180 000 Depreciation on office fixtures and fittings 11 250 Rent 90 750 Electricity 39 525 Council rates 23 475During June the company provided three services, which consumed the following quantities of professional labour (in hours): Client IT trainee IT graduate Senior consultant Robinsons 50 100 15 Smith and Son 20 140 10 Snowman Services 70 80 20 Required: 1. Calculate the predetermined overhead rate to be used at Bairstow Consulting. 2. Calculate the cost of the three services. 3. How might the management of Bairstow Consulting use this information? 4. How would Bairstow's approach differ if the firm used a billing rather than a costing system