Answer both questions with explanation

A test for a certain disease has a probability of 0.85 of detecting the disease when it is present and a probability of 0.08 of falsely detecting it when it is not present. The proportion of people afflicted by the disease for a given population is 12%. What is the probability that a randomly selected person from the district will test positive? [Answer]Incoming calls to a customer call centre come from two districts: District A (55% of calls) and district B (45% of calls). Of the callers from District A, 56% are dissatisfied with the service offered by the call center while 33% are moderately satisfied and the remaining 11% are very satisfied with the call centre service. Of the calls coming from District B, 46% are dissatisfied with the service offered by the service centre while 34% are moderately satisfied and the remaining 20% are very satisfied with the service. Suppose the last customer to call yesterday was very satisfied with the service that he got from the customer call centre. What is the probability that he was caller from District B? [Answer]