Ex.6: A service is provided through 3 types of components (e.g. database, webserver, and an application), referred with A, B and C. At least one instance of each component must be available to provide the service. One only instance is available for components A and C, whereas two instances of component B are available. Assuming that all failures and restorations are independent among them, that the failures rates of the three components A, B and C are respectively 0.2 , 0.5 and 0.3 faults per day, that the mean time to repair the components A, B, and C are respectively 2h, 3h, and 1.5h, is the service available at least 98% of the time? If not, is the availability target met deploying an additional instance of one of the components?