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 Department Subassemblies Final assembly Marketing Building occupancy Research & development Supervision Direct Costs $554, eee 779, eee 289,000 89,000 124,000 49,000 Label P1 P2 P3 S2 S2 53 Use of services by other departments is as follows. User Departments Building Marketing Occupancy @.20 Sub- assemblies 0.30 0.50 0.30 Final Assembly .20 0.50 0.30 Service Cost Center Building occupancy R&D Supervision R&D 0.20 Supervision @.10 e. 2e 0.10 0.10 The equation for department S3(supervision) is