A manufacturing company produces a particular product in an assembly-line operation. One of the machines on the line is a drill press that has single assembly line feeding into it. A partially completed unit arrives at the press to be worked on every 7.5 minutes, on average, according to an exponential distribution. The machine operator can process an average of 10 parts per hour (Poisson distributed). Determine average number of parts waiting to be worked on, the percentage of time the operator is working and the percentage of time the machine is idle