Indiana Bell customer service representatives receive an average of 1,700 calls per hour.

The time between calls follows an exponential distribution. A customer service representative can handle an average of 30 calls per hour. The time required to handle a call is also exponentially distributed. Indiana Bell can put up to 25 people on hold. If 25 people are on hold, a call is lost to the system. Indiana Bell has 75 service representatives.

1 What fraction of the time are all operators busy?

2 What fraction of all calls are lost to the system?