an office that issues student identification cards. Assume that now the students submit the documents and the photo online before coming to the office. When they arrive, they check in at the kiosk, and after they check in$,$ their record is either processed immediately or$,$ if there are some other students currently being processed, the newly arrived one is added to the queue. There is only one university worker who verifying the documents and printing the ID cards on a first$-$come$-$first$-$served basis. There is some variability both in the student arrival rate and in the time it takes a worker to process the record and print the document. When the document is printed, the student immediately picks it up and leaves.

Match the variables in this problem to the corresponding waiting time concepts.