A bank has only one typist since the typing work varies in length (Number of pages to be typed). The typing rate is randomly distributed approximating a Poisson Distribution with mean service rate of 8 letter per hour. The letter arrive at a rate of 5 per hour during the entire 8 hour work duty. If the typewriter is valued at Rs.1.50 per hour calculate :

(a) Equipment Utilization

(b) Average system time

(c) The percentage time that an arriving latter has to wait.

(d) Average cost due to waiting on the part of the typewriter.