A service facility charges a $20 fixed fee plus $25 per hour of service up to 6 hours, and no additional fee is charged for a service visit exceeding 6 hours. Suppose (for now) that the service time τ is equally likely to be any time in [0, 10] hours. (Note that τ is a continuous random variable.) Let X represent the cost of service in the facility. We would like to set up the probability density function (PDF) and the cumulative distribution function (CDF), then use them to analyze service fees