A hydraulic system consists of the following components, which are as summarised in the table below.

Components	Quantity	Failure rate per hour
Pump	1	180 10-6
Quick disconnect	3	30 10-6
Check valve	2	75 10-6
Shutoff valve	1	160 10-6
Relief valve	1	200 10-6
Lines and fittings	6	25 10-6

Assume that all components must operate for system success and that the system is used continuously throughout the year (Assume 365 days a year and 24 hours a day), with no shutdowns except for failures. Repair time varies with the type of failure, but from historical records, 60% of the repairs have required 4 hours or more to complete. Material (parts and consumables) costs have averaged R5 000 per failure. Repair labour cost is estimated to be R250 per hour.

Calculate the average cost of repairing failures of the hydraulic system per year. Assume that failure and repair times are exponentially distributed. (19)