the superior business consult

Question 15 of kaplan revison kit..how the cost per consultation is calculated ?
Calculation of the cost per consultation is as follows:
Advertising Recruitment IT Support
Number of consultants 20 30 50
Salary ($) 40,000 35,000 30,000
Total salaries 800,000 1,050,000 1,500,000
Number of consultations per annum (200 per consultant) 4,000 6,000 10,000
Business Development Activity (280 ) (1,320 ) (1,200 )
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Chargeable days 3,720 4,680 8,800
Demand for chargeable consultations 4,200 6,250 10,250
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Subcontractor days 480 1,570 1,450
Cost per subcontractor day ($) 300 220 200
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Cost of subcontractors ($) 144,000 345,400 290,000
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Cost per chargeable consultation ($)
Full-time consultants Total salaries plus operating
costs/chargeable days 277·55 286·86 232·95
Subcontractors = Cost of subcontractors/
number of subcontractors 335·71 255·71 235·71