(solution) Eighty percent of service calls regarding kitchen appliances

(solution) Eighty percent of service calls regarding kitchen appliances

Eighty percent of service calls regarding kitchen appliances involve a minor repair. For example, the customer did not read the instructions correctly or perhaps failed to connect the appliance correctly. These service calls cost  $75. Service calls for major repairs are more expensive. Fifty percent of service calls for major repairs cost the customer $300 or more. What is the probability that a randomly selected service call costs $300 or more?