Adding more checkout counters with a single line serving all counters

In this case the market can decide to build new checkout counters with each counter being served by a separate cashier $($there will be no helpers$).$ The customer at the top of the waiting line goes to whichever counter is free. While each cashier will cost $$200/$week$,$ the amortized cost of building the new counters will be $$1000/$year for each new counter added.

Taking both the capacity and waiting costs into account, which alternative is the best for the market $($assume $52$ weeks$/$year$)?$ What will be the average waiting time in the system and in the queue for the customers if the market is operating at its optimal configuration? $(40+5+5=50$ points$)$