Answer:
4.5minutes
Explanation:
The best mean minutes for fish waiting and cleaning is 4.5 minutes.
As said in the question that, clients request for this service every 8minutes, and it is a worker that is in charge of this service per branch, this means that if the worker is using 4.5 minutes to attend to a client, he or she will still have another 3.5 minutes to prepare for another customer. And this will definitely make the job easier for him or her, which means the worker will not be bombarded with request. And this will make him or her to render the best service to the customers.