The following is a system of simultaneous linear equations to allocate costs using the reciprocal method. Matrix algebra is not required. The following costs were incurred in three operating departments and three service departments in Westmoreland Company. Label P1 P2 Department Subassemblies Final assembly Marketing Building occupancy Research & development Supervision Direct Costs $550,000 775,000 285,000 85,000 120,000 45,000 P3 S1 S2 S3 Use of services by other departments is as follows. Final Assembly User Departments Building Marketing Occupancy 0.20 Sub- assemblies 0.30 0.50 0.20 Service Cost Center Building occupancy R&D 0.15 Supervision 0.10 R&D 0.25 0.50 0.30 --- --- Supervision 0.20 0.10 0.20 The equation for department P3 (marketing) is