1. If clerks represent a cost of $18 per hour and mechanics a cost of $28 per hour, what number of clerks would be optimal in terms of minimizing total cost? (6 points)

TOSHIBA The maintenance department of a elevator manufacturer (Toshiba Corporation) has a special counter used exclusively for mechanics' requests for lift spare parts. The time between requests can be modeled by a negative exponential distribution that has a mean of four minutes. A clerk can handle requests at a rate of 20 per hour, and this can be modeled by a Poisson distribution that has a mean of 20. Suppose there are two clerks at the counter. (Show your work below and support your suggestion(s) with calculations)