A residential construction company has opened a registration office. Customers arrive at the rate of $200$ per hour $($Poisson Distribution$)$ and the cost of their waiting in the queue is estimated $$100$ per person per hour. The local convention bureau provides servers to register customers at the fee of $$15$ per person per hour. Registration process takes $1$ minute $($Exponential Distribution$)$ and a single waiting line, with multiple servers is set up$.$